Tonopah Desert Tonopah Desert The Tonopah Desert is a small desert plains region of the Sonoran Desert, located west of Phoenix, Arizona. It is adjacent north of Interstate 10 and lies at the southwest intersection of the Hassayampa River with the Gila River. The Tonopah Desert is also just north of the Gila Bend Mountains massif which create the Gila Bend of the river. The Tonopah Desert is adjacent northwest of the small Palo Verde Hills on Centennial Wash. The Tonopah Desert is mostly east-west trending, small, approximately 30 mi long, and lies at the plains of low elevation mountains north; the
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