The desert that extends into northern Mexico and the southwestern United States is the Sonoran Desert. This vast desert covers parts of Arizona, California, and the Mexican states of Sonora and Baja California. Known for its unique flora, such as the saguaro cactus, the Sonoran Desert is one of the hottest deserts in North America. It provides critical habitats for numerous species, plays a role in regional climate, and hosts a variety of ecosystems, making it ecologically significant.