Cabeza Prieta Wilderness Area has the distinction of being Arizona's largest Wilderness Area, encompassing nearly 93 percent of the Cabeza Prieta National Wildlife Refuge. Designated by the Arizona Wilderness Act of 1990, the Cabeza Prieta Wilderness spans across 803,418 acres of isolated, rugged, Sonoran desert landscapes including both the Arizona Uplands and Lower Colorado components. Rugged mountains and broad desert valleys, dotted with sand dunes and lava flows, dominate the region. This is a land of solitude, shattered only by the occasional summer monsoon or the random flight of military aircraft. The military conducts overflights under a Memorandum of Understanding (MOU) and authority outlined in a special provision of the Arizona Wilderness Act of 1990. To ensure you are aware of the dangers of unexploded military ordnance, a permit and your signature on a Holdharmless Agreement is required to enter the Refuge/Wilderness. Due to illegal border crossings by both people looking for work and drug smugglers, the U.S. Customs and Border Patrol actively patrol the refuge and wilderness area. Established in 1939 to preserve a Sonoran Desert ecosystem and an at risk desert bighorn sheep population, the refuge management emphasis in the past was to manage for a healthy and thriving desert bighorn sheep population. More recently, emphasis has been placed on the endangered Sonoran pronghorn. Their numbers in the U.S. crashed to approximately 20 individuals in 2002 but since have increased to well over 200 animals thanks to an active captive breeding program. During your visit, walk carefully among the cryptogamic soils and watch for mule deer, rabbits, kangaroo rats, pocket gophers, and cactus wrens living among the chollas, creosote bushes, mesquite, ocotillo, and even the occasional elephant tree. Hot and dry, conditions at the refuge are ideal for the Saguaro forest and the many reptiles such as side-blotched lizards, desert horned lizards, Great Basin whiptails, and six species of rattlesnakes. Among these are the sidewinders, Mojave, and western diamondback rattlers. Bordered by Organ Pipe Cactus National Monument to the south and east, and the Barry M. Goldwater Range to the west and north, the Wilderness Area offers brilliant night skies, unmatched desert scenery, and a deafening desert silence. Rare experiences include a walk on a prehistoric trail, a glimpse of an endangered Sonoran pronghorn sprinting across playa lakes, and the opportunity to see wildlife and desert fauna indicative of Southwest Arizona. Across the southern half of the refuge runs an active 4-wheel-drive trail (a non-wilderness corridor), and the remains of El Camino del Diablo (The Devil's Highway), a trail first blazed in 1540. This infamous trail once connected Sonora, Mexico to California and was named for the many travelers who died along the way. Visitors are encouraged to stop by the refuge visitor center. Here, you can tour the visitor center, view an introductory video, and get your refuge permit. Staff members and volunteers will assist you in preparing for your trip. The operating hours for the visitor center are Monday through Friday, 8:00 a.m. to 4:00 p.m. Closed on holidays. At the visitor center, you can also sign the required military hold harmless agreement. The greatest obstacles to your safety include possible encounters with old mine shafts, unexploded military ordnance, illegal border activity, and a rugged, unforgiving landscape where summer temperatures routinely range above 105 degrees F during the day and remain above 90 degrees F at night. Water is scarce everywhere out here, even for the wildlife. Hikers will find no maintained trails. You must bring your own water, at least 1 to 1