HOME

TheInfoList



OR:

) of the San Francisco Bay , subdivision_type = Country , subdivision_name = United States , subdivision_type1 =
State State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * ''The State'' (newspaper), a daily newspaper in Columbia, South Carolina, United States * ''Our S ...
, subdivision_name1 =
California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...
, subdivision_type2 =
Region In geography, regions, otherwise referred to as zones, lands or territories, are areas that are broadly divided by physical characteristics ( physical geography), human impact characteristics ( human geography), and the interaction of humanity an ...
, subdivision_name2 =
San Francisco Bay Area The San Francisco Bay Area, often referred to as simply the Bay Area, is a populous region surrounding the San Francisco, San Pablo, and Suisun Bay estuaries in Northern California. The Bay Area is defined by the Association of Bay Area Go ...
, seat_type =
County seat A county seat is an administrative center, seat of government, or capital city of a county or civil parish. The term is in use in Canada, China, Hungary, Romania, Taiwan, and the United States. The equivalent term shire town is used in the US st ...
, seat = Martinez , parts_type = Largest city , parts = Concord (population and land area)
Richmond (total area) , unit_pref = US , area_total_sq_mi = 804 , area_land_sq_mi = 715.94 , area_water_sq_mi = 81 , elevation_max_footnotes = , elevation_max_ft = 3852 , population_as_of =
2020 2020 was heavily defined by the COVID-19 pandemic, which led to global social and economic disruption, mass cancellations and postponements of events, worldwide lockdowns and the largest economic recession since the Great Depression in t ...
, population_footnotes = , population_total = 1,165,927 , population_density_sq_mi = 1629 , established_title = Incorporated , established_date = February 18, 1850 , government_type = Council–CAO , governing_body = Board of Supervisors , leader_title1 = Chair , leader_name1 = Karen Mitchoff , leader_title2 = Vice Chair , leader_name2 = Federal D. Glover , leader_title3 = Board of Supervisors , leader_name3 = , leader_title4 = County Administrator Office , leader_name4 = Monica Nino , timezone = Pacific Time Zone , utc_offset = −8 , timezone_DST =
Pacific Daylight Time The Pacific Time Zone (PT) is a time zone encompassing parts of western Canada, the western United States, and western Mexico. Places in this zone observe standard time by subtracting eight hours from Coordinated Universal Time ( UTC−08:00 ...
, utc_offset_DST = −7 , postal_code_type = , postal_code = , area_code_type = Area code , area_code = 510, 341, 925 , image_map = , map_caption = Interactive map of Contra Costa County , image_map1 = Map of California highlighting Contra Costa County.svg , mapsize1 = 200px , map_caption1 = Location in the state of California , blank_name_sec1 = FIPS code , blank_info_sec1 = 06-013 , blank1_name_sec1 =
GNIS The Geographic Names Information System (GNIS) is a database of name and locative information about more than two million physical and cultural features throughout the United States and its territories, Antarctica, and the associated states of ...
feature ID , blank1_info_sec1 = , website = Contra Costa County (; ''Contra Costa'',
Spanish Spanish might refer to: * Items from or related to Spain: **Spaniards are a nation and ethnic group indigenous to Spain **Spanish language, spoken in Spain and many Latin American countries **Spanish cuisine Other places * Spanish, Ontario, Can ...
for "Opposite Coast") is a
county A county is a geographic region of a country used for administrative or other purposes Chambers Dictionary, L. Brookes (ed.), 2005, Chambers Harrap Publishers Ltd, Edinburgh in certain modern nations. The term is derived from the Old French ...
located in the U.S. state of
California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...
, in the
East Bay The East Bay is the eastern region of the San Francisco Bay Area and includes cities along the eastern shores of the San Francisco Bay and San Pablo Bay. The region has grown to include inland communities in Alameda and Contra Costa counties ...
of the
San Francisco Bay Area The San Francisco Bay Area, often referred to as simply the Bay Area, is a populous region surrounding the San Francisco, San Pablo, and Suisun Bay estuaries in Northern California. The Bay Area is defined by the Association of Bay Area Go ...
. As of the
2020 United States Census The United States census of 2020 was the twenty-fourth decennial United States census. Census Day, the reference day used for the census, was April 1, 2020. Other than a pilot study during the 2000 census, this was the first U.S. census to of ...
, the population was 1,165,927. The
county seat A county seat is an administrative center, seat of government, or capital city of a county or civil parish. The term is in use in Canada, China, Hungary, Romania, Taiwan, and the United States. The equivalent term shire town is used in the US st ...
is Martinez. It occupies the northern portion of the
East Bay The East Bay is the eastern region of the San Francisco Bay Area and includes cities along the eastern shores of the San Francisco Bay and San Pablo Bay. The region has grown to include inland communities in Alameda and Contra Costa counties ...
region of the
San Francisco Bay Area The San Francisco Bay Area, often referred to as simply the Bay Area, is a populous region surrounding the San Francisco, San Pablo, and Suisun Bay estuaries in Northern California. The Bay Area is defined by the Association of Bay Area Go ...
and is primarily suburban. The county's name refers to its position on the other side of the bay from
San Francisco San Francisco (; Spanish for " Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the fourth most populous in California and 17th ...
. Contra Costa County is included in the
San Francisco–Oakland–Berkeley, CA Metropolitan Statistical Area The San Francisco Bay Area, often referred to as simply the Bay Area, is a populous region surrounding the San Francisco, San Pablo, and Suisun Bay estuaries in Northern California. The Bay Area is defined by the Association of Bay Area Gover ...
.


History


Pre-human

In prehistoric times, particularly the
Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...
epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided by ...
, portions of the landforms now in the area (then marshy and grassy
savanna A savanna or savannah is a mixed woodland- grassland (i.e. grassy woodland) ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to ...
) were populated by a wide range of now extinct
mammals Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur o ...
, known in modern times by the
fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
remains excavated in the southern part of the county. In the northern part of the county, significant coal and sand deposits were formed in even earlier geologic eras. Other areas of the county have ridges exposing ancient but intact (not fossilized) seashells, embedded in
sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...
layers alternating with
limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...
. Layers of volcanic ash ejected from geologically recent but now extinct volcanoes, compacted and now tilted by compressive forces, may be seen at the site of some road excavations. This county is an agglomeration of several distinct geologic
terrane In geology, a terrane (; in full, a tectonostratigraphic terrane) is a crust (geology), crust fragment formed on a tectonic plate (or broken off from it) and Accretion (geology), accreted or "Suture (geology), sutured" to crust lying on another pla ...
s, as is most of the greater
San Francisco Bay Area The San Francisco Bay Area, often referred to as simply the Bay Area, is a populous region surrounding the San Francisco, San Pablo, and Suisun Bay estuaries in Northern California. The Bay Area is defined by the Association of Bay Area Go ...
, which is one of the most geologically complex regions in the world. The great local mountain
Mount Diablo Mount Diablo is a mountain of the Diablo Range, in Contra Costa County of the eastern San Francisco Bay Area in Northern California. It is south of Clayton and northeast of Danville. It is an isolated upthrust peak of , visible from most ...
has been formed and continues to be elevated by compressive forces resulting from the action of
plate tectonics Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large ...
and at its upper reaches presents ancient seabed rocks scraped from distant oceanic sedimentation locations and accumulated and lifted by these great forces. Younger deposits at middle altitudes include
pillow lava Pillow lavas are lavas that contain characteristic pillow-shaped structures that are attributed to the extrusion of the lava underwater, or ''subaqueous extrusion''. Pillow lavas in volcanic rock are characterized by thick sequences of discont ...
s, the product of undersea volcanic eruptions.


Native American period

There is an extensive but little-recorded human history pre-European settlement in this area, with the present county containing portions of regions populated by a number of Native American tribes. The earliest definitively established occupation by modern man (''
Homo sapiens Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...
'') appears to have occurred six to ten thousand years ago. However, there may have been human presence far earlier, at least as far as non–settling populations are concerned. The known settled populations were hunter-gatherer societies that had no knowledge of
metals A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typical ...
and that produced utilitarian crafts for everyday use (especially woven reed baskets) of the highest quality and with graphic embellishments of great aesthetic appeal. Extensive trading from tribe to tribe transferred exotic materials such as obsidian (useful for the making of arrowheads and other stone tools) throughout the region from far distant Californian tribes. Unlike the
nomad A nomad is a member of a community without fixed habitation who regularly moves to and from the same areas. Such groups include hunter-gatherers, pastoral nomads (owning livestock), tinkers and trader nomads. In the twentieth century, the po ...
ic Native American of the Great Plains it appears that these tribes did not incorporate warfare into their culture but were instead generally cooperative. Within these cultures the concept of individual or collective land ''ownership'' was nonexistent. Early European settlers in the region, however, did not record much about the culture of the natives. Most of what is known culturally comes from preserved contemporaneous and excavated artifacts and from inter-generational knowledge passed down through northerly outlying tribes of the larger region.


Spanish colonial

Early interaction of these Native Americans with Europeans came with the Spanish colonization via the establishment of missions in this area, with the missions in San Jose, Sonoma, and San Francisco and particularly the establishment of a
Presidio A presidio ( en, jail, fortification) was a fortified base established by the Spanish Empire around between 16th and 18th centuries in areas in condition of their control or influence. The presidios of Spanish Philippines in particular, were cen ...
(a military establishment) in 1776. Although there were no missions established within this county, Spanish influence here was direct and extensive, through the establishment of land grants from the King of Spain to favored settlers.


Mexican land grants

In 1821 Mexico gained independence from Spain. While little changed in ranchero life, the
Mexican War of Independence The Mexican War of Independence ( es, Guerra de Independencia de México, links=no, 16 September 1810 – 27 September 1821) was an armed conflict and political process resulting in Mexico's independence from Spain. It was not a single, co ...
resulted in the secularization of the missions with the re-distribution of their lands, and a new system of land grants under the Mexican Federal Law of 1824. Mission lands extended throughout the Bay Area, including portions of Contra Costa County. Between 1836 and 1846, during the era when California was a province of independent Mexico, the following 15 land grants were made in Contra Costa County. The smallest unit was one square league, or about seven square miles, or , maximum to one individual was eleven leagues, or , including no more than of irrigable land. Rough surveying was based on a map, or ''diseño'', measured by streams, shorelines, and/or horseman who marked it with rope and stakes. Lands outside rancho grants were designated ''el sobrante'', as in surplus or excess, and considered common lands. The law required the construction of a house within a year. Fences were not required and were forbidden where they might interfere with roads or trails. Locally a large family required roughly 2000 head of cattle and two square leagues of land (fourteen square miles) to live comfortably. Foreign entrepreneurs came to the area to provide goods that Mexico could not, and trading ships were taxed.For a collection of observations of the Mexican provincial culture and trading practice (most notably in the acquisition of cattle hides for eastern U.S. shoe manufacturies) see portions of ''
Two Years Before the Mast ''Two Years Before the Mast'' is a memoir by the American author Richard Henry Dana Jr., published in 1840, having been written after a two-year sea voyage from Boston to California on a merchant ship starting in 1834. A film adaptation under the ...
'', a first-person narrative of a seaman's voyage to California starting in 1834.
* Rancho Cañada de los Vaqueros was granted to Francisco Alviso, Antonio Higuera, and Manuel Miranda ( confirmed in 1889 to heirs of Robert Livermore). * Two ranchos, both called Rancho San Ramon, were granted by the Mexican government in the San Ramon Valley. In 1833, Bartolomé Pacheco (southern San Ramon Valley) and Mariano Castro (northern San Ramon Valley) shared the two square league Rancho San Ramon. José María Amador was granted a four square league Rancho San Ramon in 1834. * In 1834 Rancho Monte del Diablo (present day
Concord, California Concord ( ) is the largest city in Contra Costa County, California. According to an estimate completed by the United States Census Bureau, the city had a population of 129,295 in 2019 making it the eighth largest city in the San Francisco Bay ...
) was confirmed with to Salvio Pacheco (born July 15, 1793, died 1876). The Pacheco family settled at the Rancho in 1846 (between the
Pacheco Pacheco is a Portuguese and Spanish name which may refer to: General * Alex Pacheco (born 1958), animal rights activist, co-founder of PETA. *Ángel Pacheco (general) (1793-1869), was an Argentine military officer trained by José de San Martín ...
shipping port townsite and Clayton area, and including much of Lime Ridge). The boundary lines were designated with stone markers. Clayton was later located on El Sobrante's lands just east of Rancho Monte del Diablo (
Mount Diablo Mount Diablo is a mountain of the Diablo Range, in Contra Costa County of the eastern San Francisco Bay Area in Northern California. It is south of Clayton and northeast of Danville. It is an isolated upthrust peak of , visible from most ...
). * In 1834, Rancho Arroyo de Las Nueces y Bolbones, aka Rancho San Miguel (present day
Walnut Creek A walnut is the edible seed of a drupe of any tree of the genus ''Juglans'' (family Juglandaceae), particularly the Persian or English walnut, ''Juglans regia''. Although culinarily considered a "nut" and used as such, it is not a true bo ...
), was granted to Juana Sanchez de Pacheco, in recognition of the service of Corporal Miguel Pacheco 37 years earlier (confirmed 1853, patented to heirs 1866); the grant was for two leagues, but drawn free hand on the ''diseño''/map, and reading "two leagues, more or less" as indicated in the ''diseño'', but actually including and confirmed for nearly four leagues or nearly , but only were ever shown as having once belonged to Juana Sanchez. * 'Meganos' means 'sand dunes.' A "paraje que llaman los Méganos" 'place called the sand dunes' (with a variant spelling) is mentioned in Durán's diary on May 24, 1817. Two Los Meganos Ranchos were granted, later differentiated as Rancho Los Meganos (1835, three leagues or at least ) in what is now the Brentwood area, to Jose Noriega then acquired by
John Marsh John Marsh may refer to: Politicians * John Marsh (MP fl. 1394–1397), MP for Bath * John Marsh (MP fl. 1414–1421), MP for Bath *John Allmond Marsh (1894–1952), Canadian Member of Parliament * John Otho Marsh Jr. (1926–2019), American c ...
; and Rancho Los Medanos (to Jose Antonio Mesa and Jose Miguel Garcia, Pittsburg area, dated November 26, 1839).


Bear Flag Republic and statehood

The exclusive land ownership in California by the approximate 9,000
Hispanic The term ''Hispanic'' ( es, hispano) refers to people, cultures, or countries related to Spain, the Spanish language, or Hispanidad. The term commonly applies to countries with a cultural and historical link to Spain and to viceroyalties forme ...
s in California would soon end.
John Marsh John Marsh may refer to: Politicians * John Marsh (MP fl. 1394–1397), MP for Bath * John Marsh (MP fl. 1414–1421), MP for Bath *John Allmond Marsh (1894–1952), Canadian Member of Parliament * John Otho Marsh Jr. (1926–2019), American c ...
, owner of Rancho Los Meganos in Contra Costa County, had a lot to do with this. He sent letters to influential people in the eastern United States extolling the climate, soil, and potential for agriculture in California, with the deliberate purpose of encouraging Americans to immigrate to California and lead to its becoming part of the United States. He succeeded. His letters were published in newspapers throughout the East and started the first wagon trains rolling toward California. He also invited them to stay on his ranch until they could get settled, so the Rancho Los Meganos became the terminus of the California trail. This led to the Bear Flag Revolt in 1846 when about 30 settlers originally from the United States declared a republic in June 1846 and were enlisted and fighting under the U.S. flag by July 1846. Following the
Mexican–American War The Mexican–American War, also known in the United States as the Mexican War and in Mexico as the (''United States intervention in Mexico''), was an armed conflict between the United States and Mexico from 1846 to 1848. It followed the 1 ...
of 1846–48, California was controlled by U.S. settlers organized under the California Battalion and the
U.S. Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage o ...
's Pacific Squadron. After some minor skirmishes, California was under U.S. control by January 1847 and formally annexed and paid for by the U.S. in 1848. By 1850, California’s population of over 100,000 was rapidly growing due to the
gold rush A gold rush or gold fever is a discovery of gold—sometimes accompanied by other precious metals and rare-earth minerals—that brings an onrush of miners seeking their fortune. Major gold rushes took place in the 19th century in Australia, New ...
and the large amount of gold being exported east, which gave California enough clout to choose its own boundaries, write its own constitution, and be admitted to the Union as a free state in 1850 without going through territorial status as required for most other states. In 1850 California had a non-Indian population of over 100,000. The number of Indians living in California in 1850 has been estimated to be from 60,000 to 100,000. By 1850 the Mission Indian populations had largely succumbed to disease and abuse and only numbered a few thousand. California's 1852 state Census gives 31,266 Indian residents, but this is an under-count since there was little incentive and much difficulty in getting it more correct.


County creation

Contra Costa County was one of the original 27 counties of California, created in 1850 at the time of statehood. The county was originally to be called Mt. Diablo County, but the name was changed prior to incorporation as a county. The county's
Spanish language Spanish ( or , Castilian) is a Romance language of the Indo-European language family that evolved from colloquial Latin spoken on the Iberian peninsula. Today, it is a global language with more than 500 million native speakers, mainly in th ...
name means ''opposite coast'', because of its location opposite San Francisco, in an easterly direction, on San Francisco Bay. Southern portions of the county's territory, including all of the bayside portions opposite San Francisco and northern portions of Santa Clara County, were given up to form
Alameda County Alameda County ( ) is a county located in the U.S. state of California. As of the 2020 census, the population was 1,682,353, making it the 7th-most populous county in the state and 21st most populous nationally. The county seat is Oakland. Alam ...
effective March 25, 1853. The land titles in Contra Costa County may be traced to multiple subdivisions of a few original land grants. The grantee's family names live on in a few city and town names such as '' Martinez'', ''
Pacheco Pacheco is a Portuguese and Spanish name which may refer to: General * Alex Pacheco (born 1958), animal rights activist, co-founder of PETA. *Ángel Pacheco (general) (1793-1869), was an Argentine military officer trained by José de San Martín ...
'' and '' Moraga'' and in the names of streets, residential subdivisions, and business parks. A few mansions from the more prosperous farms have been preserved as museums and cultural centers and one of the more rustic examples has been preserved as a working demonstration ranch
Borges Ranch
In the 1860 United States Census, Contra Costa County had a population of 4,381.


1941–1945

During World War II, Richmond hosted one of the two Bay Area sites of
Kaiser Shipyards The Kaiser Shipyards were seven major shipbuilding yards located on the United States west coast during World War II. Kaiser ranked 20th among U.S. corporations in the value of wartime production contracts. The shipyards were owned by the Kaise ...
and wartime pilots were trained at what is now Concord/Buchanan Field Airport. Additionally, a large Naval Weapons Depot and munitions ship loading facilities at Port Chicago remain active to this day, but with the inland storage facilities recently declared surplus, extensive redevelopment is being planned for this last large central-county tract. The loading docks were the site of a devastating explosion in 1944. Port Chicago was bought out and demolished by the Federal Government to form a safety zone near the Naval Weapons Station loading docks. At one time the Atlas Powder Company (subsequently closed) produced gunpowder and dynamite. The site of the former Atlas Powder Company is located at
Point Pinole Regional Shoreline Point Pinole Regional Shoreline is a regional park on the shores of the San Pablo Bay, California (the northern arm of the San Francisco Bay), in the United States. It is approximately in area, and is operated by the East Bay Regional Park Dis ...
, part of the
East Bay Regional Parks District The East Bay Regional Park District (EBRPD) is a special district operating in Alameda County and Contra Costa County, California, within the East Bay area of the San Francisco Bay Area. It maintains and operates a system of regional parks which ...
.


1945-present day

With the postwar baby boom and the desire for suburban living, large
tract housing Tract housing is a type of housing development in which multiple similar houses are built on a tract (area) of land that is subdivided into smaller lots. Tract housing developments are found in suburb developments that were modeled on the " Levi ...
developers would purchase large central county farmsteads and develop them with roads, utilities and housing. Once mostly rural walnut orchards and cattle ranches, the area was first developed as low-cost, large-lot suburbs, with a typical low-cost home being placed on a "quarter-acre" (1,000 m2) lot — actually a little less at 10,000 square feet (930 m2). Some of the expansion of these suburban areas was clearly attributable to
white flight White flight or white exodus is the sudden or gradual large-scale migration of white people from areas becoming more racially or ethnoculturally diverse. Starting in the 1950s and 1960s, the terms became popular in the United States. They refer ...
from decaying areas of
Alameda County Alameda County ( ) is a county located in the U.S. state of California. As of the 2020 census, the population was 1,682,353, making it the 7th-most populous county in the state and 21st most populous nationally. The county seat is Oakland. Alam ...
and the consolidated city-county of
San Francisco San Francisco (; Spanish for " Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the fourth most populous in California and 17th ...
, but much was due to the postwar baby boom of the era creating demand for three- and four-bedroom houses with large yards that were unaffordable or unavailable in the established bayside cities. A number of large companies followed their employees to the suburbs, filling large business parks. The establishment of a large, prosperous population in turn fostered the development of large shopping centers and created demand for an extensive supporting infrastructure including roads, schools, libraries, police, firefighting, water, sewage, and flood control. The establishment of the Bay Area Rapid Transit (BART) system, the modernization of Highway 24, and the addition of a fourth
Caldecott Tunnel The Caldecott Tunnel is an east–west highway tunnel through the Berkeley Hills between Oakland and Orinda, California. Its four bores carry California State Route 24. Named after Thomas E. Caldecott, former mayor of Berkeley, it opened in 19 ...
bore all served to reinforce the demographic and economic trends in the Diablo Valley area, with cities such as
Walnut Creek A walnut is the edible seed of a drupe of any tree of the genus ''Juglans'' (family Juglandaceae), particularly the Persian or English walnut, ''Juglans regia''. Although culinarily considered a "nut" and used as such, it is not a true bo ...
and Concord becoming edge cities. The central county cities have in turn spawned their own suburbs within the county, extending east along the county's estuarine north shore; with the older development areas of Bay Point and Pittsburg being augmented by extensive development in
Antioch Antioch on the Orontes (; grc-gre, Ἀντιόχεια ἡ ἐπὶ Ὀρόντου, ''Antiókheia hē epì Oróntou'', Learned ; also Syrian Antioch) grc-koi, Ἀντιόχεια ἡ ἐπὶ Ὀρόντου; or Ἀντιόχεια ἡ ἐπ� ...
, Oakley, and Brentwood. The effects of the housing value crash (2008–2011) varied widely throughout the county. Values of houses in prosperous areas with good schools declined only modestly in value, while houses recently built in outlying suburbs in the eastern part of the county experienced severe reductions in value, accelerated by high unemployment and consequent mortgage foreclosures, owner ''strategic walk-aways'', and the too-rapid conversion of neighborhoods from owner-occupancy to rentals. Home values rebounded as the economy recovered from the recession.


Geography

According to the U.S. Census Bureau, the county has a total area of , of which is land and (11%) is water. Contra Costa County's physical geography is dominated by the bayside alluvial plain, the Oakland HillsBerkeley Hills, several inland valleys, and
Mount Diablo Mount Diablo is a mountain of the Diablo Range, in Contra Costa County of the eastern San Francisco Bay Area in Northern California. It is south of Clayton and northeast of Danville. It is an isolated upthrust peak of , visible from most ...
, an isolated 3,849-foot (1,173 m) upthrust peak at the north end of the Diablo Range of hills. The summit of Mount Diablo is the origin of the Mount Diablo Meridian and Base Line, on which the surveys of much of California and western Nevada are based. The
Hayward Fault Zone The Hayward Fault Zone is a right-lateral strike-slip geologic fault zone capable of generating destructive earthquakes. This fault is about long, situated mainly along the western base of the hills on the east side of San Francisco Bay. It runs ...
runs through the western portion of the county, from Kensington to Richmond. The
Calaveras Fault The Calaveras Fault is a major branch of the San Andreas Fault System that is located in northern California in the San Francisco Bay Area. Activity on the different segments of the fault includes moderate and large earthquakes as well as aseismi ...
runs in the south-central portion of the county, from Alamo to San Ramon. The
Concord Fault The Concord Fault is a geologic fault in the San Francisco Bay Area. The reason it is called that is because it is located under the city of Concord. It is connected to, and considered to be part of, the same fault zone as the Green Valley fault, ...
runs through part of Concord and Pacheco, and the Clayton-Marsh Creek-Greenville Fault runs from Clayton at its north end to near Livermore. These strike-slip faults and the Diablo thrust fault near Danville are all considered capable of significantly destructive earthquakes and many lesser related faults are present in the area that cross critical infrastructure such as water, natural gas, and petroleum product pipelines, roads, highways, railroads, and BART rail transit.


Sub-areas

Contra Costa County is broadly divided into three sub-areas: * West County, including of the cities of El Cerrito, Richmond, San Pablo, Pinole, and Hercules, as well as the unincorporated communities of Kensington, El Sobrante, North Richmond, Rodeo, Crockett, and Port Costa. * Central County, which is itself further divided into three areas: ** Lamorinda, including of the cities of Lafayette, Moraga, and Orinda (the name being a portmanteau of the three cities' names), as well as the unincorporated area of Canyon. ** North Central County, including of the cities of Walnut Creek, Pleasant Hill, Concord, Clayton, and Martinez, as well as the unincorporated areas of areas of Pacheco, Vine Hill, Clyde, the Pleasant Hill BART station, and Saranap. ** San Ramon Valley, including the cities of Danville and San Ramon, and the unincorporated communities of Alamo, Blackhawk, and Tassajara. * East County, including of the cities of Pittsburg, Antioch, Oakley, and Brentwood, as well as the unincorporated communities of Bay Point, Bethel Island, Knightsen, Discovery Bay, and Byron.


Adjacent counties

*
Solano County Solano County () is a county located in the U.S. state of California. As of the 2020 census, the population was 453,491. The county seat is Fairfield. Solano County comprises the Vallejo–Fairfield, CA Metropolitan Statistical Area, which i ...
- north * Sacramento County - northeast * San Joaquin County - east *
Alameda County Alameda County ( ) is a county located in the U.S. state of California. As of the 2020 census, the population was 1,682,353, making it the 7th-most populous county in the state and 21st most populous nationally. The county seat is Oakland. Alam ...
- south


National protected areas

*
Antioch Dunes National Wildlife Refuge Antioch Dunes National Wildlife Refuge is a sensitive sand dune habitat located near the city of Antioch, California on the south shore of the San Joaquin River-Stockton Deepwater Shipping Channel. It serves as a refuge for three endangered sp ...
* Eugene O'Neill National Historic Site *
John Muir National Historic Site The John Muir National Historic Site is located in the San Francisco Bay Area, in Martinez, Contra Costa County, California. It preserves the 14-room Italianate Victorian mansion where the naturalist and writer John Muir lived, as well as a ne ...
* Port Chicago Naval Magazine National Memorial * Rosie the Riveter/World War II Home Front National Historical Park


Mount Diablo

The most notable natural landmark in the county is the
Mount Diablo Mount Diablo is a mountain of the Diablo Range, in Contra Costa County of the eastern San Francisco Bay Area in Northern California. It is south of Clayton and northeast of Danville. It is an isolated upthrust peak of , visible from most ...
, at the northerly end of the Diablo Range. Mount Diablo and its neighboring North Peak are the centerpiece of Mt. Diablo State Park (MDSP), created legislatively in 1921 and rededicated in 1931 after land acquisitions had been completed. At the time this park comprised a very small portion of the mountain. In the 1960s, suburban development expanding from the surrounding valleys began to threaten the open space of the mountain. In 1971, MDSP consisted of . That year, concerned residents formed the non-profit organization
Save Mount Diablo Save, SAVE, or Saved may refer to: Places *Save (Garonne), a river in southern France *Save River (Africa), a river in Zimbabwe and Mozambique *Sava, a river in Eastern Europe also known as Save *Savè, Benin, a commune and city *Save, Govuro ...
to raise funds and awareness to protect more open space. In addition to encouraging acquisition by the state and local authorities, SMD started fundraising and acquiring properties to transfer to the park. MDSP was the first of twenty-nine Diablo-area parks and preserves that have been created around the peaks; today these preserves protect more than . These Diablo public lands stretch southeast and include the
Concord Naval Weapons Station Concord Naval Weapons Station was a military base established in 1942 north of the city of Concord, California at the shore of the Sacramento River where it widens into Suisun Bay. The station functioned as a World War II armament storage depot ...
, Shell Ridge Open Space and
Lime Ridge Open Space Lime commonly refers to: * Lime (fruit), a green citrus fruit * Lime (material), inorganic materials containing calcium, usually calcium oxide or calcium hydroxide * Lime (color), a color between yellow and green Lime may also refer to: Botany ...
s near Walnut Creek, to the State Park, and east to the
Los Vaqueros Reservoir The Los Vaqueros Reservoir and watershed is located in the northern Diablo Range, within northeastern Contra Costa County, northern California. It was completed by the Contra Costa Water District (CCWD) in to improve the quality of drinking water ...
watershed and four surrounding East Bay Regional Park District preserves, including Morgan Territory Regional Preserve, Brushy Peak Regional Preserve, Vasco Caves Regional Preserve, and Round Valley Regional Preserve. The new Marsh Creek State Park, formerly known as Cowell Ranch State Park, and
Black Diamond Mines Regional Preserve The Black Diamond Mines Regional Preserve is a park located north of Mount Diablo in Contra Costa County, California under the administration of the East Bay Regional Park District (EBRPD). The district acquired the property in 1973. The preser ...
, are among the open spaces that stretch to the north. The open spaces controlled by cities, the East Bay Regional Park District, Mount Diablo State Park, and various regional preserves now adjoin and protect most of the elevated regions of the mountain. The name Mount Diablo is said to originate from an incident involving Spanish soldiers who christened a thicket as ''Monte del Diablo'' when natives they were pursuing apparently disappeared into the thicket. Anglo settlers later misunderstood the use of the word ‘monte’ (which can mean ‘mountain’, or ‘thicket’), and applied the name to the most obvious local landmark. According to the ''Contra Costa Times'', in 2011, there were rumors that Contra Costa County was going to rename the mountain as "Mt. Ronald Reagan" or "Mt. Reagan", after the former US President and California governor. Residents have generated multiple petitions to change the name of the mountain, one in 2005 and another in 2011, but these were not successful.


Demographics


2020 census

''Note: the US Census treats Hispanic/Latino as an ethnic category. This table excludes Latinos from the racial categories and assigns them to a separate category. Hispanics/Latinos can be of any race.''


2011


Places by population, race, and income


2010 Census

The
2010 United States Census The United States census of 2010 was the twenty-third United States national census. National Census Day, the reference day used for the census, was April 1, 2010. The census was taken via mail-in citizen self-reporting, with enumerators servi ...
reported that Contra Costa County had a population of 1,049,025. The racial makeup of Contra Costa County was 614,512 (58.6%)
White White is the lightest color and is achromatic (having no hue). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully reflect and scatter all the visible wavelengths of light. White o ...
; 97,161 (9.3%)
African American African Americans (also referred to as Black Americans and Afro-Americans) are an ethnic group consisting of Americans with partial or total ancestry from sub-Saharan Africa. The term "African American" generally denotes descendants of ens ...
; 6,122 (0.6%) Native American; 151,469 (14.4%) Asian (4.6% Filipino, 3.8% Chinese, 2.1% Indian); 4,845 (0.5%)
Pacific Islander Pacific Islanders, Pasifika, Pasefika, or rarely Pacificers are the peoples of the Pacific Islands. As an ethnic/racial term, it is used to describe the original peoples—inhabitants and diasporas—of any of the three major subregions of O ...
; 112,691 (10.7%) from
other races Other often refers to: * Other (philosophy), a concept in psychology and philosophy Other or The Other may also refer to: Film and television * ''The Other'' (1913 film), a German silent film directed by Max Mack * ''The Other'' (1930 film), a ...
; and 62,225 (5.9%) from two or more races. There were 255,560 people (24.4%) of
Hispanic The term ''Hispanic'' ( es, hispano) refers to people, cultures, or countries related to Spain, the Spanish language, or Hispanidad. The term commonly applies to countries with a cultural and historical link to Spain and to viceroyalties forme ...
or Latino ancestry, of any race; 17.1% of Contra Costa County's population was of Mexican ancestry, while 1.9% was of Salvadoran heritage.


2000

As of the
census A census is the procedure of systematically acquiring, recording and calculating information about the members of a given population. This term is used mostly in connection with national population and housing censuses; other common censuses in ...
of 2000, there were 948,816 people, 344,129 households, and 242,266 families residing in the county. The population density was . There were 354,577 housing units at an average density of . Of residents who identified with European ethnicities, 9.0% were German, 7.7% Irish, 7.3% English, and 6.5% Italian ancestry according to
Census 2000 The United States census of 2000, conducted by the Census Bureau, determined the resident population of the United States on April 1, 2000, to be 281,421,906, an increase of 13.2 percent over the 248,709,873 people enumerated during the 1990 ce ...
. 74.1% spoke English, 13.1% Spanish, and 2.6% Tagalog. By 2005, 53.2% of Contra Costa County's population were non-Hispanic whites. African Americans made up 9.6% of the population, while ethnic Asians constituted 13.1%. Latinos, representing people of Spanish, Portuguese, indigenous and mestizo populations of the Western hemisphere, comprised 21.1% of the county population. In 2000, there were 344,129 households, out of which 35.4% had children under the age of 18 living with them, 54.5% were married couples living together, 11.5% had a female householder with no husband present, and 29.6% were non-families. 22.9% of all households were made up of individuals, and 8.00% had someone living alone who was 65 years of age or older. The average household size was 2.72 and the average family size was 3.23. In the county, the population was spread out, with: * 26.5% under the age of 18 * 7.7% from 18 to 24 * 30.6% from 25 to 44 * 23.9% from 45 to 64 * 11.3% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 95.4 males. For every 100 females age 18 and over, there were 92.2 males. The median income for a household in the county was $63,675, and the median income for a family was $73,039 (these figures had risen to $75,483 and $87,435 respectively as of a 2007 estimate). Males had a median income of $52,670 versus $38,630 for females. The
per capita income Per capita income (PCI) or total income measures the average income earned per person in a given area (city, region, country, etc.) in a specified year. It is calculated by dividing the area's total income by its total population. Per capita i ...
for the county was $30,615. About 5.4% of families and 7.6% of the population were below the
poverty line The poverty threshold, poverty limit, poverty line or breadline is the minimum level of income deemed adequate in a particular country. The poverty line is usually calculated by estimating the total cost of one year's worth of necessities for t ...
, including 9.8% of those under age 18 and 6.0% of those age 65 or over. In 2000, the largest denominational groups were Catholics (with 204,070 adherents) and
Evangelical Protestant Evangelicalism (), also called evangelical Christianity or evangelical Protestantism, is a worldwide interdenominational movement within Protestant Christianity that affirms the centrality of being "born again", in which an individual exper ...
s (with 74,449 adherents). The largest religious bodies were the Catholic Church (with 204,070 members) and The
Baptist General Conference Converge, formerly the Baptist General Conference (BGC) and Converge Worldwide, is an evangelical Baptist Christian denomination in United States introduced by Swedish Baptists that emerged late in the 19th century. It is affiliated with the Bap ...
(with 24,803 members). The
Rohr Jewish Learning Institute The Rohr Jewish Learning Institute (JLI) is a division of Merkos L'Inyonei Chinuch, the educational arm of the Chabad-Lubavitch Orthodox Jewish Hasidic dynasty. It offers adult Jewish courses on Jewish history, law, ethics, philosophy and ...
teaches courses in the county.


Politics

Since 1932, Contra Costa County has been a Democratic stronghold in presidential elections. It temporarily leaned toward the Republican Party in the 1970s and 1980s, with successive presidential wins by
Richard Nixon Richard Milhous Nixon (January 9, 1913April 22, 1994) was the 37th president of the United States, serving from 1969 to 1974. A member of the Republican Party, he previously served as a representative and senator from California and was ...
in 1972, Gerald Ford in 1976, and Ronald Reagan in 1980 and 1984. Reagan was the last Republican presidential candidate to win the county. In the
United States House of Representatives The United States House of Representatives, often referred to as the House of Representatives, the U.S. House, or simply the House, is the lower chamber of the United States Congress, with the Senate being the upper chamber. Together they ...
, Contra Costa County is split among four congressional districts: * * * * In the State Assembly, Contra Costa County is split among four districts: * * * * In the
State Senate A state legislature in the United States is the legislative body of any of the 50 U.S. states. The formal name varies from state to state. In 27 states, the legislature is simply called the ''Legislature'' or the ''State Legislature'', whil ...
, the county is split among three districts: * * * According to the California Secretary of State, as of October 19, 2019, Contra Costa County has 703,021 registered voters. Of those, 369,254 (52.52%) are registered Democrats, 134,553 (19.14%) are registered Republicans, and 163,047 (23.19%) have
declined to state Decline to State (DTS) was an affiliation designation on the California voter registration form that allows voters to register to vote without choosing a party affiliation. It is similar to what in other states would be called declaring oneself as ...
a political party, also known as "No Party Preference" or "NPP." Democrats hold wide advantages in voter registration numbers in all political subdivisions in Contra Costa County. The Democrats' largest registration advantage in Contra Costa is in the cities of Richmond, where there is a 60.3% registration advantage with 3,192 Republicans (6.2%) out of 51,395 registered voters compared to 34,159 Democrats (66.5%) and 12,095 voters who have no party preference (23.5%); El Cerrito, where there is a 59.0% registration advantage with 1,169 Republicans (7.4%) out of 15,877 registered voters compared to 10,543 Democrats (67.6%) and 3,654 voters who have no party preference (23.0%); and San Pablo, where there is a 58.3% registration advantage with 641 Republicans (6.1%) out of 10,550 registered voters compared to 6,793 Democrats (64.4%) and 2,746 voters who have no party preference (26.0%).


Voter registration statistics


Cities by population and voter registration


Crime

The following table includes the number of incidents reported and the rate per 1,000 persons for each type of offense.


Cities by population and crime rates (2019)


Economy


Agriculture

The great rancheros of the Spanish period were divided and sold for agricultural uses, with intensively irrigated farming made possible in some areas by the development of canals that brought water from the eastern riverside portions of the county to the central portion. Other areas could use the more limited water available from local creeks and from wells. Orchards dominated where such water was available, while other, seasonally dry areas were used for cattle ranching. In central parts of the county walnuts were an especially attractive orchard crop, using the thin-shelled English Walnut branches grafted to the hardy and disease-resistant American Walnut root stock. In the Moraga region, pears dominated, and many old (but untended) roadside trees are still picked seasonally by passers-by. In eastern county, stone fruit, especially cherries, is still grown commercially, with seasonal opportunities for people to pick their own fruit for a modest fee.


Irrigation canals

The
Contra Costa Canal The Contra Costa Canal is a aqueduct in the U.S. state of California. Its construction began in 1937, with delayed completion until 1948 due to World War II shortages in labor and materials. A portion of the canal's right of way has been develope ...
, a concrete-lined and fenced irrigation canal still makes a loop through central county and provided industrial and agricultural grade water to farms and industry. While no longer used for extensive irrigation, it is still possible for adjoining landowners (now large suburban lot owners) to obtain pumping permits. Most of this water is destined for the heavy industry near Martinez. As with the railroad rights of way there is now an extensive public trail system along these canals.


Commuter railroads

The development of commuter railroads proceeded together with the subdivision of farms into parcels. In some cases, such as the development of Saranap, the same developer controlled both the railroad ( Sacramento Northern) and the development. These early suburbanization developments were an extension of the earlier development of
trolley car suburb A streetcar suburb is a residential community whose growth and development was strongly shaped by the use of streetcar lines as a primary means of transportation. Such suburbs developed in the United States in the years before the automobile, when ...
s in what are now considered the highly urban environments of the near East Bay.


Heavy industry

Owing to its extensive waterfront on
San Francisco San Francisco (; Spanish for " Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the fourth most populous in California and 17th ...
, San Pablo, and Suisun bays the northwestern and northern segments have long been sites for heavy industry, including a number of still active oil refineries (particularly Chevron in Richmond, Shell Oil and Tesoro - in Martinez), chemical plants ( Dow Chemical) and a once substantial integrated steel plant, Posco Steel (formerly United States Steel), now reduced to secondary production of strip sheet and wire. The
San Joaquin River The San Joaquin River (; es, Río San Joaquín) is the longest river of Central California. The long river starts in the high Sierra Nevada, and flows through the rich agricultural region of the northern San Joaquin Valley before reaching Suis ...
forms a continuation of the northern boundary turns southward to form the eastern boundary of the county. Some substantial Sacramento-San Joaquin Delta "islands" (actually leveed former marshes) are included in this corner of the county.


Housing


West County

The West County is the area near or on San Francisco and San Pablo bays. The housing stock in the region was extensively developed after the great San Francisco earthquake of 1906. Much of the housing stock in these areas is becoming quite expensive. As an alternative to moving to either the expensive central county, or the too-distant East County, this area is becoming gentrified, with a mix of races and income levels — a character actively sought by some housing purchasers. The downside of this is a corresponding lack of affordable housing for those working lower-paying service jobs — a problem endemic throughout the region. There has recently been a housing boom or tract housing in Richmond and also in the
Hercules Hercules (, ) is the Roman equivalent of the Greek divine hero Heracles, son of Jupiter and the mortal Alcmena. In classical mythology, Hercules is famous for his strength and for his numerous far-ranging adventures. The Romans adapted the ...
areas. These gentrifying areas are the most diverse in Contra Costa County.


Central county

The central part of the county is a valley traversed by Interstate 680 and Highway 24. The towns east of the hills, on or near Highway 24 and their surrounding areas (
Lafayette Lafayette or La Fayette may refer to: People * Lafayette (name), a list of people with the surname Lafayette or La Fayette or the given name Lafayette * House of La Fayette, a French noble family ** Gilbert du Motier, Marquis de Lafayette (1757� ...
, Moraga and Orinda) are collectively known as ''Lamorinda''. The major central county cities along Interstate 680 are Martinez, Concord, Pleasant Hill, Walnut Creek, Danville, San Ramon, and unincorporated Alamo. Owing to the high quality of its public schools (due largely to both demographics and added support from prosperous parents), this area has become a magnet for well–off families with children. During the real estate boom, housing prices were driven to astounding levels. From 2007, home prices in the region have seen substantial decreases and the affordability rate has risen. During the real estate boom, the high price of homes and scarcity of land resulted in many speculators purchasing older, smaller homes and partially or completely tearing them down to construct larger homes. In this way the central county region has become a mix of older suburbs, newer developments, small lot "infill" developments, and extensive shopping areas.


East County

Lower cost modern tract developments continue along Suisun Bay in the "East County" towns of Pittsburg,
Antioch Antioch on the Orontes (; grc-gre, Ἀντιόχεια ἡ ἐπὶ Ὀρόντου, ''Antiókheia hē epì Oróntou'', Learned ; also Syrian Antioch) grc-koi, Ἀντιόχεια ἡ ἐπὶ Ὀρόντου; or Ἀντιόχεια ἡ ἐπ� ...
, and Oakley - new "bedroom" communities" to serve the now "edge cities". The median income of a family in the two relatively affluent East County towns of Brentwood and
Discovery Bay Discovery Bay (DB) is a resort town on Lantau Island, Hong Kong. It consists of mixed, primarily residential, development, in particular upmarket residential development and private and public recreational facilities, including garden houses, ...
is approaching $100k/yr. placing them in the top fifteen percent of affluent towns in the United States. California Distinguished Schools, golf courses, vineyards, and upscale homes are found in Brentwood and Discovery Bay. Discovery Bay is based on a waterfront community of 3,500+ homes with private docks with access to the Sacramento-San Joaquin River Delta. Discovery Bay also features gated and non-gated "off-water" communities with homes from 1,400 square feet (130 m2) up to 4,700 square feet (440 m2). In 2011, Vasco Road is undergoing further construction/improvement to reduce the driving time between East County/Brentwood and Livermore. Highway 4 is currently undergoing multimillion-dollar improvements that are scheduled to add lanes through Brentwood, Antioch and Pittsburg by 2015 to reduce the driving time between East County and Concord/Walnut Creek.


County budget problems

Across 30 years, two forces combined to create county budget problems, peaking in 2008. First, rather than compensate police, medical, and firefighting personnel directly, health and retirement benefits were granted without proper actuarial examination, leading to unexpected but predictable high costs as personnel aged and ultimately retired with continued "first class" health and retirement benefits. Second, the collapse of the "housing bubble" enabled purchasers of distressed properties — many of which were owned by banks and other mortgage holders — to petition for lower property assessments, in many cases reducing by half the revenue to the county for specific parcels. Continuing downturns in employment prospects further increased the needs for various social services. These deficits and demands, combined with a lack of support from a similarly stressed California state government and the United States Federal government, required county supervisors and service providers to allocate limited resources in a time of increasing demand. The projected budget deficit was $45 million as of early 2011. Perhaps more significantly, the total unfunded liability for retiree benefits is $2.4 billion.


Technical innovators

In the 1970s and 1980s, many small and innovative technical firms started in Contra Costa. Most of these are no longer present, either failing, being absorbed into larger corporations, or outgrowing their original location and moving elsewhere in the Bay Area.


Corporate headquarters

By the early 1990s, 22 million square feet of office space had been built along the ''680 corridor'', that segment of Interstate Highway 680 that extends from Concord in the north to San Ramon in the south, continuing into inland
Alameda County Alameda County ( ) is a county located in the U.S. state of California. As of the 2020 census, the population was 1,682,353, making it the 7th-most populous county in the state and 21st most populous nationally. The county seat is Oakland. Alam ...
from
Dublin Dublin (; , or ) is the capital and largest city of Ireland. On a bay at the mouth of the River Liffey, it is in the province of Leinster, bordered on the south by the Dublin Mountains, a part of the Wicklow Mountains range. At the 2016 c ...
to Pleasanton. During the 1980s and early 1990s, many corporations that were formerly housed in the more central metropolitan area followed their employees by moving to these large suburban and edge city office areas and office parks.


Redevelopment

There are currently political fights over the potential redevelopment of the county seat ( Martinez), with long-term residents and many elsewhere in the county concerned that it will lose its remaining small-town charm and utility in an effort to become more like the county's major recreational shopping center of
Walnut Creek A walnut is the edible seed of a drupe of any tree of the genus ''Juglans'' (family Juglandaceae), particularly the Persian or English walnut, ''Juglans regia''. Although culinarily considered a "nut" and used as such, it is not a true bo ...
. The inland portions of the
Concord Naval Weapons Station Concord Naval Weapons Station was a military base established in 1942 north of the city of Concord, California at the shore of the Sacramento River where it widens into Suisun Bay. The station functioned as a World War II armament storage depot ...
have been declared surplus by the Federal government and this area is expected to provide what is likely the last opportunity to plan and build city-sized development within the central county. This area will become a portion of the city of Concord, and planners expect that development will be confined to the lower and flatter portions of the depot, with the remainder becoming a substantial addition to the county's open space. Much of the land to be developed is relatively flat grassland and the most prominent structures are ammunition bunkers that will be removed, so future uses of the property are largely unconstrained by previous uses.


Education

The Contra Costa County Library is the county's library system.


Media

Contra Costa County receives media from the rest of the Bay Area. The City of Concord is served by the daily newspaper, the ''
East Bay Times The ''East Bay Times'' is a daily broadsheet newspaper based in Walnut Creek, California, United States, owned by the Bay Area News Group (BANG), a subsidiary of Media News Group, that serves Contra Costa County, California, Contra Costa and Al ...
'' published by the Bay Area News Group-East Bay (part of the
Media News Group MNG Enterprises, Inc., Trade name, doing business as Digital First Media and MediaNews Group, is a Denver, Colorado-based newspaper publisher owned by Alden Global Capital. The company has been growing its portfolio and as of May 2021, owns ove ...
, Denver, Colorado), with offices in
Walnut Creek A walnut is the edible seed of a drupe of any tree of the genus ''Juglans'' (family Juglandaceae), particularly the Persian or English walnut, ''Juglans regia''. Although culinarily considered a "nut" and used as such, it is not a true bo ...
. The paper was originally a paper run and owned by the Lesher family. Since the death of Dean Lesher in 1993, the paper has had several owners. The publisher also issues weekly local papers, such as the ''Concord Transcript,'' which is the local paper for Concord and nearby Clayton. In December 2019, there was a flurry of reports from reliable sources including the
Associated Press The Associated Press (AP) is an American non-profit news agency headquartered in New York City. Founded in 1846, it operates as a cooperative, unincorporated association. It produces news reports that are distributed to its members, U.S. ne ...
and the
San Francisco Chronicle The ''San Francisco Chronicle'' is a newspaper serving primarily the San Francisco Bay Area of Northern California. It was founded in 1865 as ''The Daily Dramatic Chronicle'' by teenage brothers Charles de Young and Michael H. de Young. The ...
that the 161-year-old Martinez News-Gazette, one of the longest-running newspapers in California, may have to cease publication. But as of late May 2020, the threatened cessation did not materialize and the newspaper appears to have weathered that storm. The newspaper did cease publication of a print edition effective April 2, 2020, but this was characterized as a temporary measure arising from a lack of advertising revenue. Since March 2020, this in turn arose as many local businesses were forced to suspended operations or even ceased to exist, when the area was under
shelter-in-place Shelter-in-place (SIP; also known as a shelter-in-place warning, SAME code SPW) is the act of seeking safety within the building one already occupies, rather than evacuating the area or seeking a community emergency shelter. The American Red Cro ...
regulations arising from
COVID-19 pandemic The COVID-19 pandemic, also known as the coronavirus pandemic, is an ongoing global pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The novel virus was first identi ...
. The newspaper plans to resume a full print edition when the local shelter-in-place restrictions are lifted.


Transportation

Prior to 1903, most travel to central Contra Costa County was by boat or rail to Martinez on the northern waterfront and from there to the industrial areas east along the waterfront as well as farming regions to the south. In 1903, the first tunnel through the Oakland hills (now Old Tunnel Road) was built, principally as a means of bringing hay by horse-, mule-, or ox-drawn wagons from central and eastern agricultural areas to feed the draft animals that provided the power to public and private transportation in the East Bay at the time. The tunnel exited in the hills high above the crossroads of Orinda with the road continuing on to
Lafayette Lafayette or La Fayette may refer to: People * Lafayette (name), a list of people with the surname Lafayette or La Fayette or the given name Lafayette * House of La Fayette, a French noble family ** Gilbert du Motier, Marquis de Lafayette (1757� ...
,
Walnut Creek A walnut is the edible seed of a drupe of any tree of the genus ''Juglans'' (family Juglandaceae), particularly the Persian or English walnut, ''Juglans regia''. Although culinarily considered a "nut" and used as such, it is not a true bo ...
, and Danville. The road was just wide enough for one car in each direction and had no shoulders. In 1937, the two-bore
Caldecott Tunnel The Caldecott Tunnel is an east–west highway tunnel through the Berkeley Hills between Oakland and Orinda, California. Its four bores carry California State Route 24. Named after Thomas E. Caldecott, former mayor of Berkeley, it opened in 19 ...
for road vehicles was completed, making interior Contra Costa County much more accessible. After World War II, the tunnels allowed waves of development to proceed, oriented toward Oakland rather than the northern shoreline, and the northern shoreline cities began to decline. The tunnel has since been augmented with a third bore, completed in 1964, and a fourth, completed in 2013.


Major highways

* Interstate 80 * Interstate 580 * Interstate 680 * State Route 4 * State Route 24 * State Route 160 * State Route 242 * San Pablo Avenue – formerly U.S. Route 40


Mass transit

*
Amtrak The National Railroad Passenger Corporation, doing business as Amtrak () , is the national passenger railroad company of the United States. It operates inter-city rail service in 46 of the 48 contiguous U.S. States and nine cities in Canada ...
runs its '' San Joaquins'' line to
Southern California Southern California (commonly shortened to SoCal) is a geographic and cultural region that generally comprises the southern portion of the U.S. state of California. It includes the Los Angeles metropolitan area, the second most populous urban a ...
and its ''
Capitol Corridor The ''Capitol Corridor'' is a passenger train route in Northern California operated by Amtrak between San Jose, in the Bay Area, and Auburn, in the Sacramento Valley. The route is named after the two points most trains operate between, San J ...
'' line to
Sacramento ) , image_map = Sacramento County California Incorporated and Unincorporated areas Sacramento Highlighted.svg , mapsize = 250x200px , map_caption = Location within Sacramento ...
and San Jose through stations in Richmond, Martinez, and Antioch-Pittsburg. *
BART Bart is a masculine given name, usually a diminutive of Bartholomew, sometimes of Barton, Bartolomeo, etc. Bart is a Dutch and Ashkenazi Jewish surname, and derives from the name ''Bartholomäus'', a German form of the biblical name ''Bartho ...
, a high-speed
commuter rail Commuter rail, or suburban rail, is a passenger rail transport service that primarily operates within a metropolitan area, connecting Commuting, commuters to a Downtown, central city from adjacent suburbs or commuter towns. Generally commuter r ...
system, functions as the Bay Area's metro system. **
eBART eBART (East Contra Costa County BART extension) is the project name for a hybrid rail (light rail with some features similar to commuter rail) branch line of the Bay Area Rapid Transit (BART) system in eastern Contra Costa County, California, ...
(East Contra Costa County BART extension) is designed to bring
rapid transit Rapid transit or mass rapid transit (MRT), also known as heavy rail or metro, is a type of high-capacity public transport generally found in urban areas. A rapid transit system that primarily or traditionally runs below the surface may be ...
services along the Highway 4 corridor. * AC Transit provides local service in West County and in Orinda, in addition to western Alameda County, Transbay commuter services to San Francisco, bus rapid transit lines and the bulk of All Nighter service for the
East Bay The East Bay is the eastern region of the San Francisco Bay Area and includes cities along the eastern shores of the San Francisco Bay and San Pablo Bay. The region has grown to include inland communities in Alameda and Contra Costa counties ...
. * County Connection provides local service in Central C.C. County and connecting services to Dublin and Pittsburg. * Tri-Delta Transit provides local bus service in East C.C. County and connecting regional services to Martinez, Livermore, and Stockton. *
WestCAT WestCAT is a public transportation service in western Contra Costa County (north of Oakland, CA). It is a service of the Western Contra Costa Transit Authority. The Western Contra Costa County Transit (WestCAT) was established in August 1977 as ...
provides local bus service in northern West C.C. County with connecting service to BART and transbay service to the city (San Francisco). *
Golden Gate Transit Golden Gate Transit (GGT) is a public transportation system serving the North Bay region of the San Francisco Bay Area in California, United States. It primarily serves Marin County, Sonoma County, and San Francisco, and also provides limited s ...
provides connecting transbay service between San Rafael and Richmond and El Cerrito del Norte BART stations via the Richmond-San Rafael Bridge. * Vallejo Transit and Fairfield and Suisun Transit provide regional feeder service to El Cerrito del Norte BART from
Solano County Solano County () is a county located in the U.S. state of California. As of the 2020 census, the population was 453,491. The county seat is Fairfield. Solano County comprises the Vallejo–Fairfield, CA Metropolitan Statistical Area, which i ...
. * Benicia Transit provides commuter service between the Vallejo Ferry Terminal and BART in Concord through Benicia in Solano County.


Airports

The county has two general aviation airports that are not currently providing scheduled passenger service: * Buchanan Field Airport, located in Concord * Byron Airport, located two miles (3 km) south of
Byron George Gordon Byron, 6th Baron Byron (22 January 1788 – 19 April 1824), known simply as Lord Byron, was an English romantic poet and peer. He was one of the leading figures of the Romantic movement, and has been regarded as among the ...
Concord Airport now houses two charter airlines that offer on-demand and scheduled passenger service to select destinations in California, Nevada, and Washington, plus cargo service worldwide.


Railroads

The western termini of several original transcontinental railroad routes have been located in Oakland, in
Alameda County Alameda County ( ) is a county located in the U.S. state of California. As of the 2020 census, the population was 1,682,353, making it the 7th-most populous county in the state and 21st most populous nationally. The county seat is Oakland. Alam ...
, including
Union Pacific The Union Pacific Railroad , legally Union Pacific Railroad Company and often called simply Union Pacific, is a freight-hauling railroad that operates 8,300 locomotives over routes in 23 U.S. states west of Chicago and New Orleans. Union Pac ...
, Southern Pacific, and Santa Fe railroads. From Oakland, there are two primary routes east: *The former Southern Pacific (originally Central Pacific Railroad) line north through Richmond, closely hugging the San Pablo Bay coastline to Martinez, where it crosses Suisun Bay on a drawbridge before proceeding to
Sacramento ) , image_map = Sacramento County California Incorporated and Unincorporated areas Sacramento Highlighted.svg , mapsize = 250x200px , map_caption = Location within Sacramento ...
and the crossing of the Sierra Nevada via Donner *The former Western Pacific Railroad line, which runs east through Niles Canyon, Livermore and over Altamont Pass, en route in a north-easterly direction to
Sacramento ) , image_map = Sacramento County California Incorporated and Unincorporated areas Sacramento Highlighted.svg , mapsize = 250x200px , map_caption = Location within Sacramento ...
and the
Feather River The Feather River is the principal tributary of the Sacramento River, in the Sacramento Valley of Northern California. The river's main stem is about long. Its length to its most distant headwater tributary is just over . The main stem Feather ...
canyon/
Beckwourth Pass Beckwourth Pass is the lowest mountain pass in the Sierra Nevada mountain range at an elevation of . Geography Beckwourth Pass is located at the eastern edge of Sierra Valley at Chilcoot-Vinton, California on the border between Plumas County ...
crossing of the Sierra Nevada Formed in 1909, the Oakland Antioch Railway was renamed the ''Oakland Antioch & Eastern Railway'' in 1911. It extended through a tunnel in the Oakland Hills, from Oakland to Walnut Creek, Concord and on to Bay Point. The current owner of the Santa Fe Railroad's assets, BNSF Railway, has the terminus of its transcontinental route in Richmond. Originally built by the San Francisco and San Joaquin Valley Railroad in 1896, the line was purchased by the
Atchison, Topeka and Santa Fe Railway The Atchison, Topeka and Santa Fe Railway , often referred to as the Santa Fe or AT&SF, was one of the larger railroads in the United States. The railroad was chartered in February 1859 to serve the cities of Atchison, Kansas, Atchison and Top ...
shortly thereafter. The line leaves Richmond through industrial and residential parts of West County before striking due east through Franklin Canyon and Martinez on its way to Stockton, Bakersfield, and Barstow. These railroads spurred the development of industry in the county throughout the late 19th and early 20th centuries, particularly driving development of the Standard Oil (now Chevron)
refinery A refinery is a production facility composed of a group of chemical engineering unit processes and unit operations refining certain materials or converting raw material into products of value. Types of refineries Different types of refineries ...
and port complex in Richmond. There were a large number of short lines in the county between the late 19th century and the early 20th century. The rights of way of a number of these railroads also served as utility rights of way, particularly for water service, and so were preserved and in the late 20th century enhanced as walking, jogging, and bicycle riding trails in the central portion of the county.


Attractions

*
Black Diamond Mines Regional Preserve The Black Diamond Mines Regional Preserve is a park located north of Mount Diablo in Contra Costa County, California under the administration of the East Bay Regional Park District (EBRPD). The district acquired the property in 1973. The preser ...
* Blackhawk Museum (This site also contains a
paleontological Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of foss ...
museum of the
University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public land-grant research university in Berkeley, California. Established in 1868 as the University of California, it is the state's first land-grant u ...
) * John Marsh House (not open to the public) * Eugene O'Neill National Historic Site *
John Muir National Historic Site The John Muir National Historic Site is located in the San Francisco Bay Area, in Martinez, Contra Costa County, California. It preserves the 14-room Italianate Victorian mansion where the naturalist and writer John Muir lived, as well as a ne ...
* Lindsay Wildlife Museum * Don Francisco Galindo House * Don Salvio Pacheco Adobe * Martinez Adobe * San Ramon Valley Museum *
Borges Ranch Jorge Francisco Isidoro Luis Borges Acevedo (; ; 24 August 1899 – 14 June 1986) was an Argentine short-story writer, essayist, poet and translator, as well as a key figure in Spanish-language and international literature. His best-known bo ...
*
Richmond Museum of History Richmond most often refers to: * Richmond, Virginia, the capital of Virginia, United States * Richmond, London, a part of London * Richmond, North Yorkshire, a town in England * Richmond, British Columbia, a city in Canada * Richmond, California, a ...
* Rosie the Riveter/World War II Home Front National Historical Park * Vasco Caves Regional Preserve


Parks and recreation

*
Briones Regional Park Briones Regional Park is a regional park in the East Bay Regional Park District (EBRPD) system, located in the Briones Hills of central Contra Costa County of the San Francisco Bay Area in California. Geography The park is located in rolling h ...
*
Diablo Foothills Diablo or El Diablo may refer to: Arts and entertainment Fictional entities * Diablo (Disney), a raven in ''Sleeping Beauty'' * Diablo (Marvel Comics), a Fantastic Four villain * El Diablo (comics), several fictional characters from DC Comic ...
*
Howe Homestead Park Howe may refer to: People and fictional characters * Howe (surname), including a list of people and fictional characters * Howe Browne, 2nd Marquess of Sligo (1788–1845), Irish peer and colonial governor Titles * Earl Howe, two titles, an ext ...
* Marsh Creek State Park - not open to the public *
Mount Diablo State Park Mount is often used as part of the name of specific mountains, e.g. Mount Everest. Mount or Mounts may also refer to: Places * Mount, Cornwall, a village in Warleggan parish, England * Mount, Perranzabuloe, a hamlet in Perranzabuloe parish, C ...
* Las Trampas Regional Wilderness * Shell Ridge Open Space *
Lime Ridge Open Space Lime commonly refers to: * Lime (fruit), a green citrus fruit * Lime (material), inorganic materials containing calcium, usually calcium oxide or calcium hydroxide * Lime (color), a color between yellow and green Lime may also refer to: Botany ...
* San Pablo Recreation Area ( San Pablo Dam Reservoir) *
Sugarloaf Open Space A sugarloaf was the usual form in which refined sugar was produced and sold until the late 19th century, when granulated and cube sugars were introduced. A tall cone with a rounded top was the end product of a process in which dark molasses, a r ...
* Acalanes Open Space *
Point Isabel Regional Shoreline Point Isabel Regional Shoreline in Richmond, California, is operated by East Bay Regional Park District, and is a multi-use park for joggers, windsurfers, kayakers, photographers, picnickers, and people walking dogs. It has access for pedestrians ...
in Richmond is the largest dog park in the country. *Adjoining or nearby these parks are lands of the
East Bay Municipal Utility District East Bay Municipal Utility District (EBMUD), colloquially referred to as "East Bay Mud", is a public utility district which provides water and sewage treatment services for an area of approximately in the eastern side of the San Francisco Bay. ...
. These require special annual permits for hiking, bicycle riding and horse riding, available for a small fee. At least one member of a party traversing these areas must have such a permit.


Trails

* Iron Horse Regional Trail *
California State Riding and Hiking Trail California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...
*
Contra Costa Canal Regional Trail Contra may refer to: Places * Contra, Virginia * Contra Costa Canal, an aqueduct in the U.S. state of California * Contra Costa County, California * Tenero-Contra, a municipality in the district of Locarno in the canton of Ticino in Switzerl ...
*
Delta de Anza Regional Trail Delta commonly refers to: * Delta (letter) (Δ or δ), a letter of the Greek alphabet * River delta, at a river mouth * D (NATO phonetic alphabet: "Delta") * Delta Air Lines, US * Delta variant of SARS-CoV-2 that causes COVID-19 Delta may also r ...
* Briones-Mount Diablo Regional Trail *
Lafayette-Moraga Regional Trail The Lafayette-Moraga Regional Trail is a pedestrian, bicycle, and equestrian path which runs between the cities of Lafayette and Moraga in Contra Costa county, California. It was one of the first rail-trails to be built in California. Route The ...
* Marsh Creek Regional Trail *
American Discovery Trail The American Discovery Trail is a system of recreational trails and roads that collectively form a coast-to-coast hiking and biking trail across the mid-tier of the United States. Horses can also be ridden on most of this trail. The coastal tra ...
* Hiking trails in Contra Costa County


Utilities

*
Central Contra Costa Sanitary District The Central Contra Costa Sanitary District (CCCSD), also called Central San, provides sanitary sewage transport and treatment for the central portion of Contra Costa County, California. The main facility is a per day treatment plant in resident ...
*
Contra Costa Water District The Contra Costa Water District (CCWD) is an agency that was created in 1936 to supply water for consumers in eastern Contra Costa, California. It is now one of the largest water districts in California, serving about 500,000 people in Central and E ...
*
East Bay Municipal Utility District East Bay Municipal Utility District (EBMUD), colloquially referred to as "East Bay Mud", is a public utility district which provides water and sewage treatment services for an area of approximately in the eastern side of the San Francisco Bay. ...


California casino proposals

Since 2003, four Indian gaming
casino A casino is a facility for certain types of gambling. Casinos are often built near or combined with hotels, resorts, restaurants, retail shopping, cruise ships, and other tourist attractions. Some casinos are also known for hosting live entertai ...
s have been proposed in Richmond and the surrounding area of West Contra Costa County.


Proposals

* Hilltop Mall, to be built on a site *
Lytton Rancheria Lytton may refer to: Places Australia * Lytton, Queensland ** Lytton Reach, a reach of the Brisbane River ** Electoral district of Lytton, Queensland Canada * Lytton, British Columbia, named for Edward Bulwer-Lytton ** Lytton Mountain, aka ...
at Casino San Pablo from the Scotts Valley band of the
Pomo The Pomo are an Indigenous people of California. Historical Pomo territory in Northern California was large, bordered by the Pacific Coast to the west, extending inland to Clear Lake, and mainly between Cleone and Duncans Point. One small ...
tribe and have 2,500 (originally 5,000)
slot machine A slot machine (American English), fruit machine (British English) or poker machine (Australian English and New Zealand English) is a gambling machine that creates a game of chance for its customers. Slot machines are also known pejoratively a ...
s * Point Molate Casino Resort to have a luxury shopping mall, 1,100 room hotel/resort * North Richmond to be located on a site and have a buffet


Communities


Cities

*
Antioch Antioch on the Orontes (; grc-gre, Ἀντιόχεια ἡ ἐπὶ Ὀρόντου, ''Antiókheia hē epì Oróntou'', Learned ; also Syrian Antioch) grc-koi, Ἀντιόχεια ἡ ἐπὶ Ὀρόντου; or Ἀντιόχεια ἡ ἐπ� ...
* Brentwood * Clayton * Concord * El Cerrito *
Hercules Hercules (, ) is the Roman equivalent of the Greek divine hero Heracles, son of Jupiter and the mortal Alcmena. In classical mythology, Hercules is famous for his strength and for his numerous far-ranging adventures. The Romans adapted the ...
*
Lafayette Lafayette or La Fayette may refer to: People * Lafayette (name), a list of people with the surname Lafayette or La Fayette or the given name Lafayette * House of La Fayette, a French noble family ** Gilbert du Motier, Marquis de Lafayette (1757� ...
* Martinez (county seat) * Oakley * Orinda *
Pinole Pinole, also called pinol or pinolillo, is roasted ground maize, which is then mixed with a combination of cocoa, agave, cinnamon, chia seeds, vanilla, or other spices. The resulting powder is then used as a nutrient-dense ingredient to make d ...
* Pittsburg * Pleasant Hill * Richmond * San Pablo * San Ramon *
Walnut Creek A walnut is the edible seed of a drupe of any tree of the genus ''Juglans'' (family Juglandaceae), particularly the Persian or English walnut, ''Juglans regia''. Although culinarily considered a "nut" and used as such, it is not a true bo ...


Towns

* Danville * Moraga


Census-designated places

* Acalanes Ridge * Alamo * Alhambra Valley * Bay Point * Bayview * Bethel Island *
Blackhawk Black Hawk and Blackhawk may refer to: Animals * Black Hawk (horse), a Morgan horse that lived from 1833 to 1856 * Common black hawk, ''Buteogallus anthracinus'' * Cuban black hawk, ''Buteogallus gundlachii'' * Great black hawk, ''Buteogallus uru ...
*
Byron George Gordon Byron, 6th Baron Byron (22 January 1788 – 19 April 1824), known simply as Lord Byron, was an English romantic poet and peer. He was one of the leading figures of the Romantic movement, and has been regarded as among the ...
* Camino Tassajara * Castle Hill *
Clyde Clyde may refer to: People * Clyde (given name) * Clyde (surname) Places For townships see also Clyde Township Australia * Clyde, New South Wales * Clyde, Victoria * Clyde River, New South Wales Canada * Clyde, Alberta * Clyde, Ontario, a tow ...
* Contra Costa Centre * Crockett * Diablo *
Discovery Bay Discovery Bay (DB) is a resort town on Lantau Island, Hong Kong. It consists of mixed, primarily residential, development, in particular upmarket residential development and private and public recreational facilities, including garden houses, ...
* East Richmond Heights * El Sobrante * Kensington * Knightsen * Montalvin Manor * Mountain View * Norris Canyon * North Gate * North Richmond *
Pacheco Pacheco is a Portuguese and Spanish name which may refer to: General * Alex Pacheco (born 1958), animal rights activist, co-founder of PETA. *Ángel Pacheco (general) (1793-1869), was an Argentine military officer trained by José de San Martín ...
* Port Costa * Reliez Valley * Rodeo * Rollingwood * Saranap * San Miguel * Shell Ridge * Tara Hills * Vine Hill


Unincorporated communities

* Canyon *Hasford Heights


Former communities

* Bayview-Montalvin * Port Chicago Ohmer was a rail station located on the Oakland, Antioch and Eastern Railroad 6 miles (10 km) east of Martinez, which still appeared on maps as of 1947. Though primarily just a rail station, it was sometimes referred to as a community.Purcell, Mae Fisher
History of Contra Costa County
, p. 309 (1940)


Ghost towns

* Judsonville * Nortonville * Point of Timber Landing * Somersville * Stewartville * West Hartley


Other places

* Livorna * Rossmoor - a senior development incorporated into Walnut Creek (not to be confused with the Southern California Rossmoor).


Population ranking

The population ranking of the following table is based on the 2010 census of Contra Costa County. † ''county seat''


See also

* National Register of Historic Places listings in Contra Costa County, California *
List of museums in San Francisco Bay Area, California This list of museums in the San Francisco Bay Area is a list of museums, defined for this context as institutions (including nonprofit organizations, government entities, and private businesses) that collect and care for objects of cultural, artis ...
* Stege, California, former unincorporated area within the county


Notes


References


External links

*
Contra Costa County Library

Contra Costa County Office of Education - ROP

Contra Costa Health Services

ContraCostaMeansBusiness.com - Contra Costa County's Business Portal

Contra Costa Countywide Youth Commission (CYC)

Contra Costa County Historical Society
{{Authority control California counties Counties in the San Francisco Bay Area 1850 establishments in California Populated places established in 1850 Majority-minority counties in California