Area codes 415 and 628 are

telephone A telephone, colloquially referred to as a phone, is a telecommunications device that enables two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most ...

area code A telephone numbering plan is a type of numbering scheme used in telecommunication to assign telephone numbers to subscriber telephones or other telephony endpoints. Telephone numbers are the addresses of participants in a telephone network, rea ...

s in the

North American Numbering Plan The North American Numbering Plan (NANP) is an integrated telephone numbering plan for twenty-five regions in twenty countries, primarily in North America and the Caribbean. This group is historically known as World Zone 1, World Numbering Zone ...

(NANP) for the city of

San Francisco San Francisco, officially the City and County of San Francisco, is a commercial, Financial District, San Francisco, financial, and Culture of San Francisco, cultural center of Northern California. With a population of 827,526 residents as of ...

and its northern suburbs in

Marin County Marin County ( ) is a county located in the northwestern part of the San Francisco Bay Area of the U.S. state of California. As of the 2020 census, the population was 262,231. Its county seat and largest city is San Rafael. Marin County is ac ...

(across the

Golden Gate The Golden Gate is a strait on the west coast of North America that connects San Francisco Bay to the Pacific Ocean. It is defined by the headlands of the San Francisco Peninsula and the Marin Peninsula, and, since 1937, has been spanned by ...

), and the northeast corner of

San Mateo County San Mateo County ( ), officially the County of San Mateo, is a county (United States), county located in the U.S. state of California. As of the 2020 United States census, the population was 764,442. Redwood City, California, Redwood City is th ...

in the U.S. state of

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

. Area code 415 was one of the eighty-six

original North American area codes The original North American area codes were established by the American Telephone and Telegraph Company (AT&T) in 1947. The assignment was in accord with the design of a uniform nationwide telephone numbering plan that supported the goal of dialin ...

established in 1947, but modified in geographic configuration later. Area code 628 was assigned in 2015 to form an overlay in that numbering plan area in mitigation of central office prefix exhaustion.

History

When the

American Telephone and Telegraph Company AT&T Corporation, an abbreviation for its former name, the American Telephone and Telegraph Company, was an American telecommunications company that provided voice, video, data, and Internet telecommunications and professional services to busi ...

(AT&T) introduced the first nationwide

telephone numbering plan A telephone numbering plan is a type of numbering scheme used in telecommunication to assign telephone numbers to subscriber telephones or other telephony endpoints. Telephone numbers are the addresses of participants in a telephone network, reach ...

for

Operator Toll Dialing Operator Toll Dialing was a telephone call routing and toll-switching system for the Bell System and the independent telephone companies in the United States and Canada that paved the way for Direct Distance Dialing (DDD) by telephone service subsc ...

in 1947, the state of

was divided into three numbering plan areas (NPAs) arranged as geographical zones in the southern part, the central part, and the northern part of the state. Area code 415 was assigned to central California, south of

area code 916 Area codes 916 and 279 are telephone area codes in the North American Numbering Plan for Sacramento, the state capital, and most of its suburbs. Area code 916 was one of the first three original area codes established in California in October 19 ...

, and north of

area code 213 Area codes 213, 323, and 738 are telephone area codes in the North American Numbering Plan (NANP) for the U.S. state of California. They are assigned in an overlay complex to a numbering plan area (NPA) that comprises, roughly, the area of down ...

. It stretched from

Sacramento Sacramento ( or ; ; ) is the capital city of the U.S. state of California and the seat of Sacramento County. Located at the confluence of the Sacramento and American Rivers in Northern California's Sacramento Valley, Sacramento's 2020 p ...

in the north to

Bakersfield Bakersfield is a city in and the county seat of Kern County, California, United States. The city covers about near the southern end of the San Joaquin Valley, which is located in the Central Valley region. Bakersfield's population as of the ...

in the south. In 1950, the boundaries of the numbering plan area were redrawn to produce a division of the northern and central parts along a north–south-running dividing line. Numbering plan area 415 became the coastal region from the

North Coast North Coast or Northcoast may refer to : Antigua and Barbuda * Major Division of North Coast, an urban area and major division in the parish of Saint John * North Coast, Barbuda, an administrative district of Barbuda Australia * New South Wa ...

to the

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

border, while 916 was redrawn to comprise the northeastern corner of the state. As part of this realignment, Sacramento was renumbered from area code 415 to 916, and Bakersfield to 213. With the preparations for nation-wide

direct distance dialing Direct distance dialing (DDD) is a telecommunications service in North America by which a caller may call any other subscriber outside the local calling area without operator assistance, DDD was introduced in the United States in 1951, on a tri ...

(DDD) in the early 1950s,

area code 318 Area code 318 is a telephone area code in the North American Numbering Plan (NANP) for the northern and central parts of the U.S. state of Louisiana. The area code was assigned in 1957 in an area code split of the area code 504, 504 numbering plan ...

was temporarily used in the San Francisco area, initially by customers in

Englewood, New Jersey Englewood is a city in Bergen County, in the U.S. state of New Jersey. Englewood was incorporated as a city by an act of the New Jersey Legislature on March 17, 1899, from portions of Ridgefield Township and the remaining portions of Engle ...

, participating in the first customer trials to reach the city, as well as some areas north of the

. In 1953, the entire Bay Area was "reunited" in using area code 415. Numbering plan area 415 has been split several times due to population growth and infrastructure changes. On March 1, 1959,

area code 707 Area codes 707 and 369 are telephone area codes in the North American Numbering Plan (NANP) for the northwestern part of the U.S. state of California. The area codes serve part of the northern San Francisco Bay Area, as well as the North Coast. ...

was created from the northern part, and area code 408 was created for San Jose, the South Bay, the

Monterey Bay Monterey Bay is a bay of the Pacific Ocean located on the coast of the U.S. state of California, south of the San Francisco Bay Area. San Francisco itself is further north along the coast, by about 75 miles (120 km), accessible via California S ...

, and the

Salinas Valley The Salinas Valley (Spanish language, Spanish: ''Valle de Salinas'') is one of the major valleys and most productive Agriculture, agricultural regions in California. It is located west of the San Joaquin Valley and south of San Francisco Bay and ...

. (408 has since been split to

831 __NOTOC__ Year 831 (Roman numerals, DCCCXXXI) was a common year starting on Sunday of the Julian calendar. Events By place Abbasid Empire and Byzantine Empire * Byzantine–Arab wars (780–1180)#Period of 780–842, Byzantine–Arab W ...

and overlaid with 669. 707 has since been overlaid with

369 __NOTOC__ Year 369 ( CCCLXIX) was a common year starting on Thursday of the Julian calendar. At the time, it was known as the Year of the Consulship of Galates and Victor (or, less frequently, year 1122 ''Ab urbe condita''). The denomination ...

.) On September 2, 1991, area code 510 was created 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 San Francisco Bay and San Pablo Bay. The region has grown to include inland communities in Alameda and Contra Costa counties. Wi ...

, including

Oakland Oakland is a city in the East Bay region of the San Francisco Bay Area in the U.S. state of California. It is the county seat and most populous city in Alameda County, with a population of 440,646 in 2020. A major West Coast port, Oakland is ...

. (510 has since been split to

925 Year 925 ( CMXXV) was a common year starting on Saturday of the Julian calendar. Events By date January – June * January 5 – Gabellus becomes the first abbot of the monsastery of San Martín de Albelda in the Spanish kingdom ...

and was overlaid by 341 in 2019.) On August 2, 1997,

area code 650 Area code 650 is a telephone area code in the North American Numbering Plan (NANP) for the San Francisco Bay Area in the U.S. state of California. It was split from area code 415 on August 2, 1997, and includes most of San Mateo County (except ...

was created; the partition approximately followed the boundary between San Francisco, which (along with Marin County) kept 415, and

to the south, which received the new code. Deviations from the county line included a very small area east of the

San Francisco Golf Club San Francisco Golf Club is an athletic club and private social club in San Francisco, California, It is one of the most exclusive private membership clubs in the United States. In Golfdigest's 2015-2016 ranking of America's best golf courses, S ...

, which was changed to 650, and portions of

Brisbane Brisbane ( ; ) is the List of Australian capital cities, capital and largest city of the States and territories of Australia, state of Queensland and the list of cities in Australia by population, third-most populous city in Australia, with a ...

and

Daly City Daly City () is the second-most populous city in San Mateo County, California, United States. Located in the San Francisco Bay Area, and immediately south of San Francisco (sharing its northern border with almost all of San Francisco's southern ...

, which remained in 415. On February 21, 2015, the numbering plan area was converted to an

overlay complex In telecommunications, an area code overlay complex is a telephone numbering plan that assigns multiple area codes to the same geographic numbering plan area (NPA). Area code overlays are implemented in territories of the North American Numbe ...

by adding area code 628 to the same service area, making

ten-digit dialing Ten-digit dialing is a telephone dialing procedure in the countries and territories of the North American Numbering Plan (NANP). It is the practice of including the area code of a telephone number when Dialling (telephony), dialing to initiate a t ...

mandatory in the area, with prefix ''1'' from landlines.

Service area

City and County of San Francisco

Marin County

* Bel Marin Keys *

Belvedere Belvedere (from Italian, meaning "beautiful sight") may refer to: Places Australia *Belvedere, Queensland, a locality in the Cassowary Coast Region Africa * Belvedere (Casablanca), a neighborhood in Casablanca, Morocco * Belvedere, Harare, Zi ...

* Black Point-Green Point * Bolinas *

California Park California () is a state in the Western United States that lies on the Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares an international border with the Mexican state of Baja California to the sout ...

* Corte Madera * Dogtown * Fairfax * Greenbrae *

Ignacio Ignacio is a male Spanish language, Spanish name originating in the Latin name "Ignatius" from ''ignis'' "fire". This was the name of several saints, including the Ignatius of Antioch, third bishop of Antioch (who was thrown to wild beasts by emp ...

* Inverness Park *

Inverness Inverness (; ; from the , meaning "Mouth of the River Ness") is a city in the Scottish Highlands, having been granted city status in 2000. It is the administrative centre for The Highland Council and is regarded as the capital of the Highland ...

* Kentfield * Lagunitas-Forest Knolls * Larkspur * Lucas Valley-Marinwood * Manor * Marconi * Marin City *

Marshall Marshall may refer to: Places Australia *Marshall, Victoria, a suburb of Geelong, Victoria ** Marshall railway station Canada * Marshall, Saskatchewan * The Marshall, a mountain in British Columbia Liberia * Marshall, Liberia Marshall Is ...

* McNears Beach *

Mill Valley Mill Valley is a city in Marin County, California, United States, located about north of San Francisco via the Golden Gate Bridge and from Napa Valley. The population was 14,231 at the 2020 United States census, 2020 census. Mill Valley is lo ...

* Muir Beach * Nicasio *

Novato Novato (Spanish for "Novatus") is a city in Marin County, California, United States, situated in the North Bay region of the San Francisco Bay Area. At the 2020 census, Novato had a population of 53,225. History What is now Novato was origi ...

* Olema * Paradise Cay * Point Reyes Station * Ross * San Anselmo *

San Geronimo San Geronimo or San Gerónimo may refer to: Places Argentina * San Gerónimo, San Luis, a village in central Argentina Bolivia * San Geronimo River Chile * San Gerónimo Aerodrome, an airport near Algarrobo, Valparaiso Dominican Republic * ...

San Quentin San Quentin Rehabilitation Center (SQ), formerly known as San Quentin State Prison, is a California Department of Corrections and Rehabilitation state prison for men, located north of San Francisco in the unincorporated place of San Quentin in ...

* San Rafael * Santa Venetia *

Sausalito Sausalito (Spanish for "small willow grove") is a city in Marin County, California, United States, located southeast of Marin City, south-southeast of San Rafael, and about north of San Francisco from the Golden Gate Bridge. Sausalito's p ...

* Sleepy Hollow * Stinson Beach *

Strawberry The garden strawberry (or simply strawberry; ''Fragaria × ananassa'') is a widely grown Hybrid (biology), hybrid plant cultivated worldwide for its fruit. The genus ''Fragaria'', the strawberries, is in the rose family, Rosaceae. The fruit ...

* Tamalpais-Homestead Valley * Tiburon * Woodacre

San Mateo County

References

External links

{{coord, 38, -122.6, region:US-CA_type:adm2nd, display=title 415 Culture of San Francisco 415 Marin County, California Northern California Telecommunications-related introductions in 1947 Telecommunications-related introductions in 2015