North American Desert:
 The vast arid region between the Rocky Mountains and Sierra Nevada of western North America, encompassing all four major American deserts.
North America has four major deserts: the Great Basin, the Mojave, the Chihuahuan and the Sonoran. All but the Sonoran Desert have cold winters

n 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.