The Sonoran Desert is a North American desert. It covers large parts of the Southwestern United States in Arizona and California. It also covers parts of Northwestern Mexico. This includes Sonora, Baja California and Baja California Sur. It is the hottest desert in North America. The Sonoran Desert has an area of . The western portion of the United States–Mexico border goes through the Sonoran Desert. It is the hottest desert in North America. It is known for its giant Saguaro cactuses.