This list of North American deserts identifies areas of the continent which receive less than annual precipitation. The "North American Desert" is also the term for a large U.S. Level 1 ecoregion (EPA) of the North American Cordillera, in the Deserts and xeric shrublands biome (WWF). The continent's deserts are largely between the Rocky Mountains and Sierra Madre Oriental on the east, and the rain shadow-creating Sierra Nevada, Transverse, and Peninsular Ranges on the west. The North American xeric region of over includes: 3 major deserts; numerous smaller deserts; and large non-desert arid regions; in the western United States and in northeast, central, and northwest Mexico.