Unit 45B, Arizona

Elevation ranges from approximately 700 feet on the desert flats to around 3,100 feet on the higher Kofa Mountain ridges. The landscape alternates between broad, gently sloping desert plains cut by dry washes and abruptly rising, rocky mountain terrain featuring sheer cliffs, loose and broken footing, and deep drainages. Backcountry navigation requires topographic maps; much of the bighorn habitat is physically demanding and inaccessible by vehicle.

Unit 45B lies entirely within Kofa National Wildlife Refuge (USFWS), which is essentially 100% public land. Vehicle travel is restricted to designated roads and must remain within 100 feet of those roads; off-road travel, cross-country retrieval, and travel in washes off designated routes is prohibited. All motorized vehicles must be registered, insured, and street-legal with valid Arizona safety equipment. Key access corridors include King Valley Road from the Stone Cabin area on US-95 south of Quartzsite running east to Double O Junction, then northeast to the Big Dick Road area; Hovatter Road off I-10 west of Tonopah providing eastern access; and Engesser Road from the Whitewing Ranch area north of Dateland for southern approaches. Internal refuge roads connect to named water sources including Craven Well, Red Rock Pass, Hoodoo Well, and Sheep Tank Mine area. The Kofa Wilderness — part of the refuge — is essentially roadless; hunters targeting bighorn sheep in the interior should plan for multi-day backcountry camps. High-clearance 4WD is required on most roads. Administered by USFWS Kofa Refuge (928-783-7861). Firearm use on the refuge must comply with all provisions of state and local law and applicable refuge regulations.

Sonoran Desert scrub dominates, with a plant community of palo verde, velvet mesquite, catclaw acacia, ironwood, and saguaro cactus. Desert washes support denser riparian vegetation. The mountains contain rocky, cactus-studded slopes with limited grass cover. No pinyon-juniper or higher-elevation conifer component exists at these elevations.

Desert bighorn sheep are the primary managed game species and the reason the refuge was established in 1939. The refuge population is estimated at approximately 428 individuals across the Kofa and Castle Dome Mountains. Bighorn occupy the rocky Kofa Mountain core, with concentrations around High Tank 3 (White Dykes Dam), Red Rock Pass to Sheep Tank Mine, Hoodoo Well to Moonshine-Yaqui Tanks, and Polaris Mountain; lower densities occur in the Tank Mountains. Desert mule deer are present throughout the unit, concentrated in desert washes and valley floors; the population is considered low-density. Gambel's quail populations fluctuate with annual precipitation. Coyotes, kit foxes, badgers, and desert tortoise are present. Mountain lion have established a permanent presence on the refuge, which is considered a contributing factor in bighorn population dynamics.