Basin and Range

Sunrise over Death Valley, California, USA. This emotive name is supposed to have been given to the valley in 1849, when a group of pioneering settlers travelled through this forbidding desert region. The valley is about 209 km/130 mi long and its lowest point, at Badwater, lies 86 m/282 ft below sea level.

Region that is part of the Intermontane Region in the USA and Mexico. Covering over 777,000 sq km/300,000 sq mi within the USA, the region occupies most of the state of Nevada as well as parts of Utah, Oregon, Idaho, California, Arizona, New Mexico, and Texas. It takes its name from its main structural characteristic, the alternation of mountain ranges with the valleys or depressions known as basins (the most famous of which is California's Death Valley).

The Basin and Range region lies between the Columbia Plateau (north), the Wasatch Range and Colorado Plateau (east), and the Cascade Range and Sierra Nevada (west), and extends southeast into Texas and south into the Mexican states of Sonora and Chihuahua. The Colorado River and its tributaries drain the province to the Gulf of California (the Pacific Ocean), while the Rio Grande, along with the Pecos River and other tributaries, run to the Gulf of Mexico (the Atlantic Ocean). However, except for a few other peripheral streams, drainage in the region is mostly internal, with water being channelled into playas, salt lakes, and sinks, some of them vestiges of the huge glacial Lakes Bonneville and Lahontan. Because it lies in the rain shadow (east) of California's mountains, the region is largely arid. Lack of usable water and harsh terrain have kept it for the most part uninhabited. Activities here include mining, stock raising, and military exercises. Residential, resort, and agricultural development have arisen where extensive irrigation has been undertaken.

The ranges are the result of the tilting of fault blocks, sections of the earth's crust turned upwards by large plate movements; they are generally east-facing, with gradual westward slopes. The basins generally result from the corresponding lowering of crustal sections; some, for example Death Valley, now lie well below sea level. The province is sometimes identified with the Great Basin, which is its largest constituent part (accounting for over 60% of its area). Overall, however, the province also includes the lower Sonoran Desert and Salton Trough (site of California's Imperial Valley and Salton Sea), as well as higher areas extending through southeastern New Mexico and into the Great Bend region of Texas.