Sonoran Desert The Sonoran Desert (sometimes also called Gila Desert after Gila River) is a North American desert which straddles part of the U.S.-Mexico border and covers large parts of the U.S. states of Arizona and California and the Mexican state of Sonora. It is one of the largest and hottest deserts in North America, with an area of 120,000 square miles (311,000 kmē). The desert contains a variety of unique plants and animals, such as the saguaro cactus. On January 17, 2001, 496,337 acres (2,008 kmē) of the Sonoran Desert was set aside as the Sonoran Desert National Monument for the purpose of enhancing resource protection. The Sonoran Desert wraps around the northern end of the Gulf of California, from northeastern Baja California through southeastern California and southwestern Arizona to western Sonora. It is bounded on the west by the Peninsular Ranges, which separate it from the California chaparral and woodlands and Baja California desert ecoregions of the Pacific slope. To the north, the Sonoran Desert transitions to the cold-winter Mojave, Great Basin, and Colorado Plateau deserts. To the east, the deserts transition to the coniferous Arizona Mountains forests and Sierra Madre Occidental forests at higher elevations. The Sonoran-Sinaloan transition subtropical dry forest marks the transition from the Sonoran Desert to the tropical dry forests of Sinaloa. The desert's subregions include the Colorado Desert and Yuma Desert. In the 1951 publication, Vegetation of the Sonoran Desert, Forrest Shreve divided the Sonoran Desert into seven regions according to characteristic vegetation: Lower Colorado Valley, Arizona Upland, Plains of Sonora, Foothills of Sonora, Central Gulf Coast, Vizcaino Region, and Magdalena Region. (see An Overview of the Sonoran Desert, external link below). Many ecologists now consider Shreve's Vizcaino and Magdalena regions, which lie on the western side of the Baja California Peninsula, to be a separate ecoregion, the Baja California desert. From Wikipedia, the free encyclopedia