Geography

The Basin and Range Province

Texas’s smallest geographic region is in far West Texas, bounded by New Mexico to the north, the Rio Grande to the south and west, and the Toyah Basin/Stockton Plateau to the east. Rain is very slight and erratic in this area—the average annual rainfall in El Paso is about 8 miniscule inches—and most of the land is divided into large ranches.

The Basin and Range Province also contains a small portion of the Rocky Mountain system, though geologists continue to debate this claim. This entire area is also referred to as the mythical Trans-Pecos region, a rugged landscape that has captured the imagination of those who appreciate the beauty of nature in a panoramic and isolated setting.

This area is also home to the state’s three main mountain ranges, the Guadalupe Mountains along the southern New Mexico border (home to the state’s highest point, the 8,749-foot Guadalupe Peak), the Davis Mountains just north of Big Bend, and the Franklin Mountains in El Paso. Big Bend National Park [1], located along the biggest bend of the Rio Grande, contains the Chisos Mountains, where the highest elevation, Emory Peak, reaches a respectable 7,832 feet.

The basins of the region are noteworthy for not having a drainage outlet to the nearby Rio Grande. Instead, they channel the scant rainfall into “salt lakes.” These areas are typically dry as a bone, and the exposed solid minerals in their beds were once a major source for commercial salt.

The Great Plains

In its entirety, this region extends all the way from Canada to Central Texas’s Balcones Fault. It may seem like a stretch to connect these seemingly polar opposite regions of North America, but for the Panhandle residents who experience subfreezing temperatures when “blue northers” blow in, it’s a chilling reality.

Because of its rocky surface composition, this region contains a variety of physical features, from the High Plains in the north to the Edwards Plateau in the south. The geologic structure of the Great Plans region also produces some of Texas’s most breathtaking natural features. Palo Duro Canyon near Amarillo is a multi-colored, otherworldly sight to behold, and the Hill Country’s [2] magnificent Enchanted Rock [3] is a massive pink dome of solid granite that has beckoned people for centuries with its mystic aura.

This portion of the state is considered by many to be the most compelling and evocative region of Texas, especially in the southwestern area, which transforms into the fabled Trans-Pecos region. It’s big sky country, where the surrounding natural beauty is astounding. Endless vistas, colorful rock formations, and the magnificent blue sky are tourist attractions unto themselves, drawing visitors from across the globe that consider wide open spaces to be merely a myth.

The western portion of the Panhandle is known as the Llano Estacado, or Staked Plains. According to legend, Spanish explorer Francisco Vasquez de Coronado marked his trek through the area with wooden stakes since the area was (and still is) virtually void of physical landmarks. The lack of water—rainfall and rivers are scarce in the area—has been problematic throughout the history of the High Plains. Perhaps as a concession, the region inherited mineral wealth in the form of oil and natural gas deposits. These petroleum gold mines were discovered in the 1920s in the Panhandle and in the Permian Basin area near the cities of Midland and Odessa.

The southern portion of this region, the Edwards Plateau, is marked by the Balcones Escarpment, a geologic rift in the underlying layers of rock stretching roughly from Del Rio eastward to Austin [4]. This area has a thin limestone-based soil and is primarily used for cattle, sheep, and goat ranching, resulting in its distinction as one of the major regions for wool and mohair production in the country.

The Interior Lowlands

Much like Texas’s Great Plains, the Interior Lowlands extend from North Texas through the Midwestern United States all the way to Canada. An abundance of rivers, hills, and cultivable land tie Texas’s Interior Lowlands to its mid-continent neighbors, resulting in its largely agricultural use. Unlike the arid conditions of the Basin and Range Province, this region averages up to 30 inches of rain annually.

Within the Interior Lowlands are several subregions, including the North Central Plains, which comprise roughly two-thirds of the entire region. This area is marked by rolling hills and the West Texas Rolling Plains, which are just as their name implies—pleasant yet unimposing.

Other subregions also reflect their natural nomenclature—the Western and Eastern Cross Timbers and the Grand Prairie. These three areas stretch eastward to Fort Worth [5], and are primarily home to cattle ranches and crops such as wheat and cotton. The region’s absence of a major water-producing aquifer necessitated the construction of several reservoirs for irrigation as well as strict conservation regulations. Two of Texas’s major rivers, the Trinity and Brazos, also traverse the area, allowing agricultural production of cotton and grain to continue.

The Gulf Coastal Plains

The last of Texas’s geographic regions is its largest, comprising the southern and eastern third of the state. This area has the lowest elevation in Texas—less than 1,000 feet above sea level—and contains several bands of physical features and soil types formed by the weathering of underlying rock layers. As its name implies, the Gulf Coastal Plains include Texas’s entire coastline and the mouths of most of the state’s major rivers.

The Pine Belt comprises the eastern portion of this region along the Louisiana border. Pine trees, hay fields, and cattle pastures dominate the area, which is home to several national forests and the state’s lumber industry. The region’s natural features also include two major oil fields—Spindletop near Beaumont [6] and the East Texas Oil Field.

West of the Pine Belt lie the Post Oak and Blackland Belts. These regions are known for their fertile soil and rolling prairies, and cotton remains the major crop. Settlers coveted the clear streams and quality soil in the Blackland Belt, which stretches east from Del Rio and northward through San Antonio [7], Austin [4], Waco [8], and Dallas [9]. The prime agricultural conditions fueled Texas’s growth, and the region retains some of the state’s most densely populated areas.

Texas’s southern tip is mostly comprised of the Rio Grande Plain, which includes the Lower Rio Grande Valley, known throughout the state simply as “the Valley.” The Rio Grande Plain extends southward into Mexico for several hundred miles. Much of the area is covered with cacti, mesquite trees, and wild shrubs. Cattle production is also significant in the southern Rio Grande Plains, including the famous King Ranch [10] located southwest of Corpus Christi [11]. The Valley, meanwhile, thrives agriculturally, thanks to the rich delta soils and absence of freezing weather.

The region’s Coastal Prairies stretch across the Gulf of Mexico coastline, reaching as far as 60 miles inland. The eastern portion of this region is thick with vegetation and supports crops ranging from rice to cotton. The southern portion contains grasslands, citrus fruits, and vegetables.