The Sonoran Desert covers large parts of the states of Arizona, California, and Sonora (Mexico). It has an area of 120,000 square miles (311,000 square kilometers).

The Sonoran Desert contains the northern end of the Gulf of California, from northeastern Baja through southeastern California and southwestern Arizona all the way to the western side of Sonora. It is bordered on the west by the Peninsular Ranges, which separate it from the California chaparral, woodlands, and the Baja California desert. In the north, the Sonoran Desert transitions into the cold winter Mojave, Great Basin, and Colorado Plateau deserts.