Painted Desert (Arizona) plateau's south border the Mogollon Rim, the north border of the Arizona transition zone. Owing to the strong rain shadow of the Mogollon Rim, the Painted Desert has a cold desert climate (Köppen "BWk"), with hot, dry summers and cold, though virtually snow-free winters. The annual precipitation is the lowest in northern Arizona and in many places is lower even than Phoenix. Much of the region is accessible only by foot or unpaved road though major highways and paved roads cut across the area. The towns of Cameron and Tuba City, both on the Navajo Nation, are two major settlements.
Desert bighorn sheep the population is 18,965-19,040. The results of the state-by-state survey are shown to the right. In southern California, by 1998, only 280 individuals of the peninsular bighorn sheep population remained, and that population was added to the list of the United States' most imperiled species. Populations in three southern counties had suffered greatly from disease, development, and predation. As of 2008, about 800 peninsular bighorns are believed to populate the desert backcountry from the US-Mexico border to the San Jacinto Mountains, with known populations in Anza-Borrego Desert State Park. These gains, combined with Bush Administration policies, prompted the US Fish