The geography of Texas is diverse and large. Occupying about 7% of the total water and land area of the U.S., it is the second largest state after

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U ...

, and is the southernmost part of the

Great Plains The Great Plains (french: Grandes Plaines), sometimes simply "the Plains", is a broad expanse of flatland in North America. It is located west of the Mississippi River and east of the Rocky Mountains, much of it covered in prairie, steppe, a ...

, which end in the south against the folded

Sierra Madre Oriental The Sierra Madre Oriental () is a mountain range in northeastern Mexico. The Sierra Madre Oriental is part of the American Cordillera, a chain of mountain ranges (cordillera) that consists of an almost continuous sequence of mountain ranges that f ...

Mexico Mexico (Spanish language, Spanish: México), officially the United Mexican States, is a List of sovereign states, country in the southern portion of North America. It is borders of Mexico, bordered to the north by the United States; to the so ...

Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...

is in the

South Central United States The South Central United States or South Central states is a region in the south central portion of the Southern United States. It evolved out of the Old Southwest, which originally was the western portion of the South. The states of Arkansas, ...

of America, and is considered to form part of the

U.S. South The Southern United States (sometimes Dixie, also referred to as the Southern States, the American South, the Southland, or simply the South) is a geographic and cultural region of the United States of America. It is between the Atlantic Ocean ...

and also part of the

U.S. Southwest The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural region of the United States that generally includes Arizona, New Mexico, and adjacent portions of California, Colorado, N ...

. By residents, the state is generally divided into

North Texas North Texas (also commonly called North Central Texas) is a term used primarily by residents of Dallas, Fort Worth, and surrounding areas to describe much of the north central portion of the U.S. state of Texas. Residents of the Dallas–Fort Wo ...

East Texas East Texas is a broadly defined cultural, geographic, and ecological region in the eastern part of the U.S. state of Texas that comprises most of 41 counties. It is primarily divided into Northeast and Southeast Texas. Most of the region co ...

Central Texas Central Texas is a region in the U.S. state of Texas surrounding Austin and roughly bordered by San Saba to Bryan and San Marcos to Hillsboro. Central Texas overlaps with and includes part of the Texas Hill Country and corresponds to a ...

South Texas South Texas is a region of the U.S. state of Texas that lies roughly south of—and includes—San Antonio. The southern and western boundary is the Rio Grande, and to the east it is the Gulf of Mexico. The population of this region is about 4.96 ...

West Texas West Texas is a loosely defined region in the U.S. state of Texas, generally encompassing the arid and semiarid lands west of a line drawn between the cities of Wichita Falls, Abilene, and Del Rio. No consensus exists on the boundary betw ...

and, sometimes, the

Panhandle A salient (also known as a panhandle or bootheel) is an elongated protrusion of a geopolitical entity, such as a subnational entity or a sovereign state. While similar to a peninsula in shape, a salient is most often not surrounded by water on ...

, but according to the ''

Texas Almanac The Texas Almanac is a biennially published reference work providing information for the general public on the history of the US state of Texas and its people, government and politics, economics, natural resources, holidays, culture, education, rec ...

'', Texas has four major physical regions: Gulf Coastal Plains, Interior Lowlands, Great Plains, and Basin and Range Province. This has been cited as the difference between

human geography Human geography or anthropogeography is the branch of geography that studies spatial relationships between human communities, cultures, economies, and their interactions with the environment. It analyzes spatial interdependencies between social ...

and

physical geography Physical geography (also known as physiography) is one of the three main branches of geography. Physical geography is the branch of natural science which deals with the processes and patterns in the natural environment such as the atmosphere ...

, although the fact that Texas was granted the prerogative to divide into as many as five U.S. states may be a historical motive for Texans defining their state as containing exactly five regions. Some regions in Texas are more associated with the American Southeast (primarily East Texas, Central Texas, and North Texas), while the Panhandle is considered by many to have more in common with parts of the plains Midwest than either the South or Southwest. Geographically and culturally, El Paso is closer to New Mexico or Arizona than it is to Austin or to East Texas. The size of Texas prohibits easy categorization of the entire state wholly in any recognized region of the United States, and even

cultural diversity Cultural diversity is the quality of diverse or different cultures, as opposed to monoculture, the global monoculture, or a homogenization of cultures, akin to cultural evolution. The term "cultural diversity" can also refer to having different c ...

among regions of the state makes it difficult to treat Texas as a region in its own right.

Physical geography

Texas covers a total area of . The longest straight-line distance is from the northwest corner of the panhandle to the

Rio Grande The Rio Grande ( and ), known in Mexico as the Río Bravo del Norte or simply the Río Bravo, is one of the principal rivers (along with the Colorado River) in the southwestern United States and in northern Mexico. The length of the Rio G ...

river just below Brownsville, . The greatest east–west distance is from the extreme eastward bend in the Sabine River in Newton County to the extreme western bulge of the

just above El Paso. The largest continental state is so expansive that El Paso, in the western corner of the state, is closer to

San Diego, California San Diego ( , ; ) is a city on the Pacific Ocean coast of Southern California located immediately adjacent to the Mexico–United States border. With a 2020 population of 1,386,932, it is the eighth most populous city in the United Stat ...

, than to the

Houston Houston (; ) is the most populous city in Texas, the most populous city in the Southern United States, the fourth-most populous city in the United States, and the sixth-most populous city in North America, with a population of 2,304,580 ...

Beaumont Beaumont may refer to: Places Canada * Beaumont, Alberta * Beaumont, Quebec England * Beaumont, Cumbria * Beaumont, Essex ** Beaumont Cut, a canal closed in the 1930s * Beaumont Street, Oxford France (communes) * Beaumont, Ardèche * ...

area, near the Louisiana state line; while Orange, on the border with Louisiana, is closer to

Jacksonville, Florida Jacksonville is a city located on the Atlantic coast of northeast Florida, the most populous city proper in the state and is the largest city by area in the contiguous United States as of 2020. It is the seat of Duval County, with which th ...

, than it is to El Paso. Texarkana, in the northeastern corner of the state, is about the same distance from

Chicago, Illinois (''City in a Garden''); I Will , image_map = , map_caption = Interactive Map of Chicago , coordinates = , coordinates_footnotes = , subdivision_type = Country , subdivision_name ...

, as it is from El Paso, and

Dalhart Dalhart is a city in Dallam and Hartley counties in the U.S. state of Texas, and the county seat of Dallam County. The population was 7,930 at the 2010 census. History Founded in 1901, Dalhart is named for its location on the border of Dall ...

, in the northwestern corner of the state, is closer to the state capitals of

Kansas Kansas () is a U.S. state, state in the Midwestern United States, Midwestern United States. Its Capital city, capital is Topeka, Kansas, Topeka, and its largest city is Wichita, Kansas, Wichita. Kansas is a landlocked state bordered by Nebras ...

Nebraska Nebraska () is a state in the Midwestern region of the United States. It is bordered by South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Kansas to the south; Colorado to the sout ...

Colorado Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of the ...

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe, New Mexico, Santa Fe , LargestCity = Albuquerque, New Mexico, Albuquerque , LargestMetro = Albuquerque metropolitan area, Tiguex , Offi ...

Oklahoma Oklahoma (; Choctaw: ; chr, ᎣᎧᎳᎰᎹ, ''Okalahoma'' ) is a state in the South Central region of the United States, bordered by Texas on the south and west, Kansas on the north, Missouri on the northeast, Arkansas on the east, New ...

and

Wyoming Wyoming () is a state in the Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the southwest, and Colorado to t ...

than it is to

Austin Austin is the capital city of the U.S. state of Texas, as well as the seat and largest city of Travis County, with portions extending into Hays and Williamson counties. Incorporated on December 27, 1839, it is the 11th-most-populous city ...

, its own state capital. The geographic center of Texas is about northeast of Brady in northern McCulloch County.

Guadalupe Peak Guadalupe Peak, also known as Signal Peak, is the highest natural point in Texas, with an elevation of above sea level. It is located in Guadalupe Mountains National Park, and is part of the Guadalupe Mountains range in southeastern New Mexico a ...

, at above

sea level Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardis ...

, is the highest point in Texas, the lowest being sea level where Texas meets the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United ...

. Texas has five state forests and 120

state park State parks are parks or other protected areas managed at the sub-national level within those nations which use "state" as a political subdivision. State parks are typically established by a state to preserve a location on account of its natural ...

s totalling over . There are 3,700 named streams and 15 major river systems flowing through of Texas, supporting over 212

reservoirs A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including control ...

. With 10

climatic regions Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorological ...

, 14 soil regions, and 11 distinct ecological regions, regional classification becomes problematic with differences in soils, topography, geology, rainfall, and plant and animal communities.

Coast and estuaries

Much of the Gulf coastline of Texas is paralleled by the

Texas barrier islands The Texas barrier islands are a chain of barrier islands in the Gulf of Mexico along the Texas Gulf Coast. The islands enclose a series of estuaries along the Texas coast and attract tourists for activities such as recreational fishing and dolphin ...

, many of which enclose a series of estuaries where the state's rivers mix with water from the Gulf of Mexico. These water bodies include some of the largest and most ecologically productive coastal estuaries in the United States and contribute significantly to the ecological and economic resources of Texas.

Coastal Plains

The

Gulf Coastal Plains The Gulf Coastal Plain extends around the Gulf of Mexico in the Southern United States and eastern Mexico. This coastal plain reaches from the Florida Panhandle, southwest Georgia, the southern two-thirds of Alabama, over most of Mississippi, we ...

extends from the Gulf of Mexico inland to the

Balcones Fault The Balcones Fault or Balcones Fault Zone is an area of largely normal faulting Edwards Aquifer in the U.S. state of Texas that runs roughly from the southwest part of the state near Del Rio to the north-central region near Dallas along In ...

and the Eastern Cross Timbers. This large area stretches from the cities of

Paris Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. Si ...

San Antonio ("Cradle of Freedom") , image_map = , mapsize = 220px , map_caption = Interactive map of San Antonio , subdivision_type = Country , subdivision_name = United States , subdivision_type1= State , subdivision_name1 = Texas , subdivision_ ...

to Del Rio but shows a large variety in vegetation. Ranging from of annual rainfall, this is a nearly level, drained plain dissected by streams and rivers flowing into coastal estuaries and

marsh A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found ...

es. Windblown sands and dunes, grasslands, oak mottes and salt marshes make up the seaward areas.

National Park A national park is a natural park in use for conservation purposes, created and protected by national governments. Often it is a reserve of natural, semi-natural, or developed land that a sovereign state declares or owns. Although individual ...

s include

Big Thicket National Preserve The Big Thicket is the name given to a somewhat imprecise region of a heavily-forested area of Southeast Texas in the United States. This area represents a portion of the mixed pine-hardwood forests of southeast US. The National Park Service esta ...

Padre Island National Seashore Padre Island National Seashore (PINS) is a national seashore located on Padre Island off the coast of South Texas. In contrast to South Padre Island, known for its beaches and vacationing college students, PINS is located on North Padre Isla ...

and the Palo Alto Battlefield National Historic Site.

North Central Plains

The North Central Plains are bounded by the

Caprock Escarpment The Caprock Escarpment is a term used in West Texas and Eastern New Mexico to describe the geographical transition point between the level High Plains of the Llano Estacado and the surrounding rolling terrain. In Texas, the escarpment stretches ...

to the west, the

Edwards Plateau The Edwards Plateau is a geographic region at the crossroads of Central, South, and West Texas. It is bounded by the Balcones Fault to the south and east, the Llano Uplift and the Llano Estacado to the north, and the Pecos River and Chihua ...

to the south, and the Eastern Cross Timbers to the east. This area includes the North Central Plains around the cities of Abilene and

Wichita Falls Wichita Falls ( ) is a city in and the seat of government of Wichita County, Texas, United States. It is the principal city of the Wichita Falls Metropolitan Statistical Area, which encompasses all of Archer, Clay, and Wichita counties. According ...

, the Western Cross Timbers to the west of

Fort Worth Fort Worth is the fifth-largest city in the U.S. state of Texas and the 13th-largest city in the United States. It is the county seat of Tarrant County, covering nearly into four other counties: Denton, Johnson, Parker, and Wise. Accord ...

, the

Grand Prairie Grand Prairie is a city in Dallas, Tarrant, and Ellis counties of Texas, in the United States. It is part of the Mid-Cities region in the Dallas–Fort Worth metroplex. It had a population of 175,396 according to the 2010 census, making it ...

, and the Eastern Cross Timbers to the east of

Dallas Dallas () is the third largest city in Texas and the largest city in the Dallas–Fort Worth metroplex, the fourth-largest metropolitan area in the United States at 7.5 million people. It is the largest city in and seat of Dallas County ...

. With about annual rainfall, gently rolling to hilly forested land is part of a larger pine-hardwood forest of oaks, hickories, elm and gum trees. Soils vary from coarse sands to tight clays or shet rock clays and

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especiall ...

Great Plains

The

include the

Llano Estacado The Llano Estacado (), sometimes translated into English as the Staked Plains, is a region in the Southwestern United States that encompasses parts of eastern New Mexico and northwestern Texas. One of the largest mesas or tablelands on the Nort ...

, the

, Toyah Basin, and the

Llano Uplift The Llano Uplift is a geologically ancient, low geologic dome that is about in diameter and located mostly in Llano, Mason, San Saba, Gillespie, and Blanco counties, Texas. It consists of an island-like exposure of Precambrian igneous and m ...

. It is bordered on the east by the

in the panhandle and by the

to the southeast. Cities in this region include Midland and

Odessa Odesa (also spelled Odessa) is the third most populous city and municipality in Ukraine and a major seaport and transport hub located in the south-west of the country, on the northwestern shore of the Black Sea. The city is also the administrativ ...

Lubbock Lubbock ( ) is the 10th-most populous city in the U.S. state of Texas and the seat of government of Lubbock County. With a population of 260,993 in 2021, the city is also the 85th-most populous in the United States. The city is in the northw ...

, and

Amarillo Amarillo ( ; Spanish for " yellow") is a city in the U.S. state of Texas and the seat of Potter County. It is the 14th-most populous city in Texas and the largest city in the Texas Panhandle. A portion of the city extends into Randall Cou ...

. The Hill Country is a popular name for the area of hills along the

Balcones Escarpment The Balcones Fault or Balcones Fault Zone is an area of largely normal faulting Edwards Aquifer in the U.S. state of Texas that runs roughly from the southwest part of the state near Del Rio to the north-central region near Dallas along Inte ...

and is a transitional area between the

and the

. With about annual rainfall, the southern end of the Great Plains are gently rolling plains of shrub and grassland, and home to the dramatic Caprock Canyons and Palo Duro Canyon state parks. The largest concentration of playa lakes in the world (nearly 22,000) is on the Southern High Plains of Texas and Eastern

. Texas's blackland prairies were some of the first areas farmed in Texas. Highly expansive

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay pa ...

s with characteristic dark coloration, called the Houston Black series, occur on about 1.5 million acres (6,000 km²) extending from north of Dallas south to San Antonio. The Professional Soil Scientists Association of Texas has recommended to the State Legislature that the

Black series be designated the State soil. The series was established in 1902. National Parks in this area are the Lyndon B. Johnson National Historical Park and the

San Antonio Missions National Historical Park San Antonio Missions National Historical Park is a National Historical Park and part of a UNESCO World Heritage Site preserving four of the five Spanish frontier missions in San Antonio, Texas, USA. These outposts were established by Catholic re ...

Mountains and basins

The

Trans-Pecos The Trans-Pecos, as originally defined in 1887 by the Texas geologist Robert T. Hill, is the portion of Texas that lies west of the Pecos River. The term is considered synonymous with Far West Texas, a subdivision of West Texas. The Trans-Peco ...

Natural Region has less than annual rainfall. The most complex Natural Region, it includes Sand Hills, the Stockton Plateau, desert valleys, wooded mountain slopes and desert grasslands. The

Basin and Range Province The Basin and Range Province is a vast physiographic region covering much of the inland Western United States and northwestern Mexico. It is defined by unique basin and range topography, characterized by abrupt changes in elevation, alternating ...

is in West Texas, west of the

Pecos River The Pecos River ( es, Río Pecos) originates in north-central New Mexico and flows into Texas, emptying into the Rio Grande. Its headwaters are on the eastern slope of the Sangre de Cristo mountain range in Mora County north of Pecos, New Mexic ...

, beginning with the

Davis Mountains The Davis Mountains, originally known as Limpia Mountains, are a range of mountains in West Texas, located near Fort Davis, after which they are named. The fort was named for then United States Secretary of War and later Confederate President J ...

on the east and the

to its west and south. The Trans-Pecos region is the only part of Texas regarded as mountainous and includes seven named peaks in elevation greater than . This region includes sand hills, desert valleys, wooded mountain slopes and desert grasslands. The vegetation diversity includes at least 268

grass Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns a ...

species and 447 species of

woody plant A woody plant is a plant that produces wood as its structural tissue and thus has a hard stem. In cold climates, woody plants further survive winter or dry season above ground, as opposite to herbaceous plants that die back to the ground until sp ...

s. National Parks include the

Amistad National Recreation Area Amistad National Recreation Area is a national recreation area managed by National Park Service (NPS) that includes the area around the Amistad Reservoir at the confluence of the Rio Grande, the Devils River, and the Pecos River near Del Rio ...

Big Bend National Park Big Bend National Park is an American national park located in West Texas, bordering Mexico. The park has national significance as the largest protected area of Chihuahuan Desert topography and ecology in the United States, and was named after ...

Chamizal National Memorial Chamizal National Memorial, located in El Paso, Texas, along the United States–Mexico international border, is a National Park Service site commemorating the peaceful settlement of the Chamizal boundary dispute. Facility The memorial par ...

Fort Davis National Historic Site Fort Davis National Historic Site is a United States National Historic Site located in the unincorporated community of Fort Davis, Jeff Davis County, Texas. Located within the Davis Mountains of West Texas, the historic site was established ...

Guadalupe Mountains National Park Guadalupe Mountains National Park is an American national park in the Guadalupe Mountains, east of El Paso, Texas. The mountain range includes Guadalupe Peak, the highest point in Texas at , and El Capitan used as a landmark by travelers on the ro ...

, and the Rio Grande Wild and Scenic River. This area is part of the

Chihuahuan Desert The Chihuahuan Desert ( es, Desierto de Chihuahua, ) is a desert ecoregion designation covering parts of northern Mexico and the southwestern United States. It occupies much of far West Texas, the middle to lower Rio Grande Valley and the lo ...

Climate

Continental,

Mountain A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher ...

, and Modified Marine are the three major climatic types of Texas, with no distinguishable boundaries. Modified Marine, or subtropical, dominates the majority of the state. Texas has an annual

precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...

range from in Jasper County, East Texas, to in El Paso. The record high of was reached at

Seymour Seymour may refer to: Places Australia * Seymour, Victoria, a township * Electoral district of Seymour, a former electoral district in Victoria * Rural City of Seymour, a former local government area in Victoria * Seymour, Tasmania, a localit ...

on 12 August 1936, and Monahans on 28 June 1994. The low also ties at in Tulia on 12 February 1899, and

Seminole The Seminole are a Native American people who developed in Florida in the 18th century. Today, they live in Oklahoma and Florida, and comprise three federally recognized tribes: the Seminole Nation of Oklahoma, the Seminole Tribe of Florida, ...

on 8 February 1933.

Geology

Texas is mostly

sedimentary rocks Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particle ...

, with East Texas underlain by a

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

and younger sequence of sediments, the trace of ancient shorelines east and south until the

active continental margin A continental margin is the outer edge of continental crust abutting oceanic crust under coastal waters. It is one of the three major zones of the ocean floor, the other two being deep-ocean basins and mid-ocean ridges. The continental margin ...

of the

is met. This sequence is built atop the subsided crest of the

Appalachian Mountains The Appalachian Mountains, often called the Appalachians, (french: Appalaches), are a system of mountains in eastern to northeastern North America. The Appalachians first formed roughly 480 million years ago during the Ordovician Period. The ...

–

Ouachita Mountains The Ouachita Mountains (), simply referred to as the Ouachitas, are a mountain range in western Arkansas and southeastern Oklahoma. They are formed by a thick succession of highly deformed Paleozoic strata constituting the Ouachita Fold and Thru ...

– Marathon Mountains zone of Pennsylvanian

continental collision In geology, continental collision is a phenomenon of plate tectonics that occurs at convergent boundaries. Continental collision is a variation on the fundamental process of subduction, whereby the subduction zone is destroyed, mountains produ ...

, which collapsed when

rifting In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben wi ...

Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...

time opened the Gulf of Mexico. West from this

orogenic Orogeny is a mountain building process. An orogeny is an event that takes place at a convergent plate margin when plate motion compresses the margin. An ''orogenic belt'' or ''orogen'' develops as the compressed plate crumples and is uplifted t ...

crest, which is buried beneath the

–

Waco Waco ( ) is the county seat of McLennan County, Texas, United States. It is situated along the Brazos River and I-35, halfway between Dallas and Austin. The city had a 2020 population of 138,486, making it the 22nd-most populous city in the s ...

–

trend, the sediments are

Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleo ...

and

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest per ...

in age.

Oil An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) & lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturated ...

is found in the Cretaceous sediments in the east, the Permian sediments in the west, and along the Gulf coast and out on the Texas

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...

. A few exposures of

Precambrian The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of th ...

igneous Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or ...

and

metamorphic rock Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, caus ...

s are found in the central and western parts of the state, and

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but t ...

volcanic A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plat ...

rocks are found in far west Texas, in the Big Bend area. A blanket of

Miocene The Miocene ( ) is the first 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 means "less recen ...

sediments known as the

Ogallala formation The Ogallala Formation is a Miocene to early Pliocene geologic formation in the central High Plains of the western United States and the location of the Ogallala Aquifer. In Nebraska and South Dakota it is also classified as the Ogallala Group. ...

in the western high plains region is an important

aquifer An aquifer is an underground layer of water-bearing, permeable rock, rock fractures, or unconsolidated materials ( gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characte ...

. Texas has no active or dormant volcanoes and few earthquakes, being situated far from an active

plate tectonic 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 te ...

boundary. The Big Bend area is the most seismically active; however, the area is sparsely populated and suffers minimal damages and injuries, and no known fatalities have been attributed to a Texas earthquake.

Resources

With a large supply of

natural resource Natural resources are resources that are drawn from nature and used with few modifications. This includes the sources of valued characteristics such as commercial and industrial use, aesthetic value, scientific interest and cultural value. ...

s, Texas is a major

agricultural Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled peopl ...

and industrial state, producing oil, cattle, sheep, and cotton. The state also produces poultry, eggs, dairy products, greenhouse and nursery products, wheat, hay, rice, sugar cane, and peanuts, and a range of fruits and vegetables. *

Asphalt Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term ...

-bearing rocks, mainly cretaceous limestones, occur in Bexar, Burnet, Kinney, Uvalde, and other counties. *

Cement A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel (aggregate) together. Cement mixe ...

is produced in Bexar, Comal, Dallas, Ector, Ellis, El Paso, Harris, Hays, McLennan, Nolan, Nueces, Potter, and Tarrant counties. Historically, Texas' Portland cement output accounts for about 10% of the annual United States production. *With an abundance of various types of

s, Texas is one of the leading producers of clays. *

Bituminous coal Bituminous coal, or black coal, is a type of coal containing a tar-like substance called bitumen or asphalt. Its coloration can be black or sometimes dark brown; often there are well-defined bands of bright and dull material within the seams. It ...

occurs primarily in Coleman, Eastland, Erath, Jack, McCulloch, Montague, Palo Pinto, Parker, Throckmorton, Wise, and Young counties of Texas.

Lignite Lignite, often referred to as brown coal, is a soft, brown, combustible, sedimentary rock formed from naturally compressed peat. It has a carbon content around 25–35%, and is considered the lowest rank of coal due to its relatively low heat ...

, or brown coal, occurs in deposits in the Texas Coastal Plain. *Fluorspar or

fluorite Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF2. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon. The Mohs sca ...

is an important industrial mineral used in the manufacture of

steel Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistan ...

, aluminum,

glass Glass is a non- crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenchin ...

, and fluorocarbons. It occurs at several localities in the Trans-Pecos and Llano regions of Texas. *Collecting

gemstone A gemstone (also called a fine gem, jewel, precious stone, or semiprecious stone) is a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks (such as lapis lazuli, opal, ...

rock and mineral specimens has proved quite profitable.

Agate Agate () is a common rock formation, consisting of chalcedony and quartz as its primary components, with a wide variety of colors. Agates are primarily formed within volcanic and metamorphic rocks. The ornamental use of agate was common in Anci ...

jasper Jasper, an aggregate of microgranular quartz and/or cryptocrystalline chalcedony and other mineral phases,Kostov, R. I. 2010. Review on the mineralogical systematics of jasper and related rocks. – Archaeometry Workshop, 7, 3, 209-213PDF/ref ...

cinnabar Cinnabar (), or cinnabarite (), from the grc, κιννάβαρι (), is the bright scarlet to brick-red form of mercury(II) sulfide (HgS). It is the most common source ore for refining elemental mercury and is the historic source for the bri ...

topaz Topaz is a silicate mineral of aluminium and fluorine with the chemical formula Al Si O( F, OH). It is used as a gemstone in jewelry and other adornments. Common topaz in its natural state is colorless, though trace element impurities can mak ...

calcite Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scratc ...

opal Opal is a hydrated amorphous form of silica (SiO2·''n''H2O); its water content may range from 3 to 21% by weight, but is usually between 6 and 10%. Due to its amorphous property, it is classified as a mineraloid, unlike crystalline form ...

petrified wood Petrified wood, also known as petrified tree (from Ancient Greek meaning 'rock' or 'stone'; literally 'wood turned into stone'), is the name given to a special type of '' fossilized wood'', the fossilized remains of terrestrial vegetation. ' ...

, and

tektites Tektites (from grc, τηκτός , meaning 'molten') are gravel-sized bodies composed of black, green, brown or grey natural glass formed from terrestrial debris ejected during meteorite impacts. The term was coined by Austrian geologist Franz ...

are all commonly collected. *Deposits of

graphite Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on la ...

occur in the Llano region and was previously produced in Burnet County. *Bat

guano Guano (Spanish from qu, wanu) is the accumulated excrement of seabirds or bats. As a manure, guano is a highly effective fertilizer due to the high content of nitrogen, phosphate, and potassium, all key nutrients essential for plant growth. G ...

occurs in numerous caverns in the Edwards Plateau and in the Trans-Pecos region and to a more limited extent in Central Texas. *

Gypsum Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and drywa ...

is extensively developed in Texas where the main occurrences are in the Permian Basin, the Cretaceous Edwards Formation in Gillespie and Menard counties, and the

Gulf Coast The Gulf Coast of the United States, also known as the Gulf South, is the coast, coastline along the Southern United States where they meet the Gulf of Mexico. The list of U.S. states and territories by coastline, coastal states that have a shor ...

salt domes of Harris County and previously Brooks County. *Texas is the leading producer of

helium Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic ta ...

solely from the Cliffside gas field near Amarillo. *Deposits of

iron ore Iron ores are rocks and minerals from which metallic iron can be economically extracted. The ores are usually rich in iron oxides and vary in color from dark grey, bright yellow, or deep purple to rusty red. The iron is usually found in the ...

are present in northeastern Texas as well as several in Central Texas. *Elements of the

Lanthanide The lanthanide () or lanthanoid () series of chemical elements comprises the 15 metallic chemical elements with atomic numbers 57–71, from lanthanum through lutetium. These elements, along with the chemically similar elements scandium and yt ...

series are commonly termed rare-earth elements. Several of the rare earths have anomalous concentrations in the

rhyolitic Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals ( phenocrysts) in an otherwise fine-grained groundmass. The ...

and related igneous rocks in the Trans-Pecos area of Texas. A deposit containing several rare-earth minerals was exposed at Barringer Hill in Llano County before it was covered by the waters of Lake Buchanan. *

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 w ...

s, abundant in many parts of Texas, are used in the manufacture of lime. Plants for the production of lime are operating in Bexar, Bosque, Burnet, Comal, Deaf Smith, Hill, Johnson, Nueces, and Travis counties. *

Magnesium chloride Magnesium chloride is the family of inorganic compounds with the formula , where x can range from 0 to 12. These salts are colorless or white solids that are highly soluble in water. These compounds and their solutions, both of which occur in natu ...

magnesium sulfate Magnesium sulfate or magnesium sulphate (in English-speaking countries other than the US) is a chemical compound, a salt with the formula , consisting of magnesium cations (20.19% by mass) and sulfate anions . It is a white crystalline solid, ...

and other mineral salts are present in the Upper Permian Basin and in the underlying playas of the High Plains. *

Manganese Manganese is a chemical element with the Symbol (chemistry), symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of ...

is known to occur in

rocks in Mason and Llano counties, in Val Verde County, in Jeff Davis County, and in Dickens County. *

Mica Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into extremely thin elastic plates. This characteristic is described as perfect basal cleavage. Mica is ...

is present in Precambrian pegmatite in the Llano region. *Common

occurs on the Texas Coastal Plain. *

Salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quant ...

s occurs in large quantities in salt domes in the Texas Coastal Plain and with other evaporites in the Permian Basin of West Texas, as well as near

Grand Saline, Texas Grand Saline is a city in Van Zandt County, Texas, United States, located in East Texas. The population was 3,136 as of 2010. Grand Saline is the third largest city in Van Zandt County and is located roughly 75 miles (120 km) east of Dallas an ...

. *

Sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class ...

s used for industrial purposes commonly have been found in the Texas Coastal Plains, East Texas, north central Texas, and Central Texas; and sand mines have opened in the Shinnery (dunes) ecosystem of northern West Texas and the eastern part of the West Wingtip. *The discovery of

silver Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical ...

in Texas has been credited by some to Franciscans who discovered and operated mines near El Paso about 1680. Documented silver production started in the late 1880s at the Presidio Mine, in Presidio County. Texas produced 32,663,405 troy ounces of silver between 1885 and 1955. *

Sulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formul ...

occurs in the caprocks of salt domes in the Gulf Coastal Plain, in Permian-age bedded deposits in Trans-Pecos Texas. *In the past,

uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...

was produced from surface mines in Atascosa, Gonzales, Karnes, and Live Oak counties. All uranium mines are closed and Texas is no longer a producer. *The

Barnett Shale The Barnett Shale is a geological formation located in the Bend Arch-Fort Worth Basin. It consists of sedimentary rocks dating from the Mississippian period (354–323 million years ago) in Texas. The formation underlies the city of Fort Worth ...

, located in the Fort Worth basin, has gained attention in recent years as a source of natural gas. Controversy regarding drilling and exploration rights is an issue.

References

External links

The State of Texas websiteAnnual precipitation mapTNRIS
— the Texas Natural Resources Information System
Big Bend National Park in context of earth's history
{{U.S. political divisions geographies