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North American DesertsDeserrUSA

In most modern classifications, the deserts of the United States and northern Mexico are grouped into four distinct categories. These distinctions are made on the basis of floristic composition and distribution -- the species of plants growing in a particular desert region. Plant communities, in turn, are determined by the geologic history of a region, the soil and mineral conditions, the elevation and the patterns of precipitation.

Three of these deserts -- the Chihuahuan, the Sonoran and the Mojave -- are called "hot deserts," because of their high temperatures during the long summer and because the evolutionary affinities of their plant life are largely with the subtropical plant communities to the south. The Great Basin Desert is called a "cold desert" because it is generally cooler and its dominant plant life is not subtropical in origin.

Chihuahuan Desert: A small area of southeastern New Mexico and extreme western Texas, extending south into a vast area of Mexico.
Great Basin Desert: The northern three-quarters of Nevada, western and southern Utah, to the southern third of Idaho and the southeastern corner of Oregon. According to some, it also includes small portions of western Colorado and southwestern Wyoming. Bordered on the south by the Mojave and Sonoran Deserts.
Mojave Desert: A portion of southern Nevada, extreme southwestern Utah and of eastern California, north of the Sonoran Desert.
Sonoran Desert: A relatively small region of extreme south-central California and most of the southern half of Arizona, east to almost the New Mexico line.

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Desert Disagreements

This classification of North American Deserts is by no means universally accepted by all biologists, geologists and other scientists. For instance, some maintain that the Mojave is not a distinct desert at all, but simply a transition zone between the Great Basin and Sonoran deserts. Even among those who agree upon this classification, there is disagreement over the exact geographic areas circumscribed by each of the four deserts. Some scientists would use animals and other criteria, as well as distribution of plant species, to determine desert different boundaries for these four deserts.

The Colorado Plateau is another major source of disagreement among scientists. This semiarid region of southern Utah and northern Arizona contains many majestic national parks, including Arches and Grand Canyon. Yet, experts cannot agree on the desert classification of this geologically distinct region. Some do not include the Colorado Plateau within any desert at all; others call this area the Painted Desert; still others, DesertUSA included, consider this region the southeastern extent of the Great Basin Desert.

An additional source of confusion is provided by the great number of desert names (i.e. Yuman Desert, Colorado Desert, etc.) that do not match any of the four major deserts listed above. These names usually refer to local subdivisions within one of the four major deserts. These "deserts" are identified and defined below.

Other Desert Names & Subdivisions

Arizona Upland Desert: That elevated portion of the Sonoran Desert in southern Arizona characterized by Saguaro Cactus.

Black Rock Desert: A subdivision of the Great Basin Desert located in northwestern Nevada just northeast of Pyramid Lake.

Borrego Desert: The portion of the Sonoran Desert area just west of the the Salton Trough of southeast California.

Colorado Desert: The California portion of the Sonoran Desert west of the Colorado River.

Escalante Desert: A subdivision of the Great Basin desert just west of Cedar Breaks in southwestern Utah.

Great American Desert: An ill-defined, semiarid region of the Great Plains, or, all of the North American deserts combined.

Great Sandy Desert: A subdivision of the Great Basin Desert located in southeastern Oregon.

Northern Mojave Desert: The Mojave north of Las Vegas, Nevada.

Magdalena Desert: The Sonoran Desert on the lowest third of the Baja Peninsula.

North American Desert: The vast arid region between the Rocky Mountains and Sierra Nevada of western North America, encompassing all four major American deserts

Painted Desert: This term is used differently by different writers:

A narrow desert strip running west of the Grand Canyon, north-to-south along U.S. Route 89, then turning east along Interstate 40 to just beyond Petrified Forest National Monument.
OR
The entire region from the northern boundary of the Sonoran Desert of Arizona to southwestern Colorado and southern Utah, encompassing the Colorado River, the Colorado Plateau and its numerous parks and monuments.

Red Desert: The semiarid region of southwestern Wyoming, sometimes considered an extension of the Great Basin Desert.

Sevier Desert: A subdivision of the Great Basin desert just northwest of Delta in south-central Utah.

Smoke Creek Desert: A subdivision of the Great Basin Desert located in northwestern Nevada abutting the north end of Pyramid Lake.

Southern Mojave Desert: The Mojave south of Las Vegas, Nevada.

Trans-Pecos Desert: The Chihuahuan Desert west of Texas' Pecos River.

Upland Desert: (See Arizona Upland Desert.)

Vizcaino Desert: The Sonoran Desert on the middle third of the Baja Peninsula.

Yuha Desert:That portion of the Sonoran Desert between Ocotillo and El Centro, California, south across the Mexican border.

Yuma Desert: That portion of the Sonoran Desert just east of the Colorado River near Yuma, Arizona.