Unit 43B

Key landmarks guide movement through this maze of washes and open country. The Trigo and Middle Mountains provide visual references across the broad valleys. Lighthouse Rock stands out as a distinctive navigation marker.

The Colorado River itself—visible or accessible via Martinez Lake, Mittry Lake, and Imperial Reservoir—anchors the western boundary and serves as a major drainage corridor. Los Angeles Wash, Yuma Wash, and numerous smaller washes cut across the unit, offering natural travel routes and concentration points. Red Hill and Mohave Peak provide minor vantage points for glassing the surrounding flats.

The unit spans extreme low-desert terrain, rising from near sea level along the Colorado River to approximately 2,700 feet in the surrounding mountains. The majority of the country sits below 1,000 feet—wide, flat desert valleys studded with creosote, palo verde, and sparse sagebrush. The Trigo and Middle Mountains, along with smaller ranges like the Laguna and Mohave ranges, break the horizon with low, rocky peaks and ridges offering modest elevation gain.

Higher bajadas support scattered desert shrubland; lower flats become increasingly open. This is classic Sonoran Desert habitat with minimal forest cover.

Roughly 493 miles of roads thread through the unit, with U.S. Highway 95 serving as the primary east-west corridor. Castle Dome Road and King Road provide interior access. However, the vast area and sparse road network create significant travel distances between access points.

Much of the unit requires off-road navigation across open desert. Most pressure concentrates along Highway 95 and near river-access points; inland valleys and lower mountains see limited hunter presence. The combination of vast size and limited infrastructure means solitude is achievable but requires accepting long walks from vehicle.

Unit 43B straddles the lower Colorado River in southwestern Arizona, bounded by the Arizona-California state line on the west and south, I-8 to the southwest, U.S. Highway 95 to the east, and the Kofa National Wildlife Refuge to the north. The unit encompasses roughly 1,500 square miles of Sonoran Desert with scattered low mountain ranges separated by broad alluvial valleys. Castle Dome and several ghost towns mark historical settlements within the unit's boundary.

The landscape transitions from river-bottom riparian habitat near Mittry Lake and Martinez Lake to open desert basins and low, rocky ranges inland.

The Colorado River is the unit's primary water source, with several reservoirs providing reliable surface water: Martinez Lake, Mittry Lake, and Imperial Reservoir. However, water away from the river corridor is genuinely scarce. The Gila Gravity Main Canal and associated irrigation channels follow the river but support limited wildlife use.

Numerous washes—Yuma, Los Angeles, Black Rock, Fortuna, and others—flow intermittently during storms but remain dry much of the year. Hunters must plan water access carefully; early season often requires hauling water or depending on the river system.

Unit 43B holds desert bighorn sheep in the low mountain ranges—the Trigo, Middle, Laguna, and Mohave ranges offer the best habitat, though populations are modest. Mule deer inhabit bajadas and wash corridors, especially where vegetation is denser. Javelina thrive in creosote flats and lower foothills.

Mountain lion and black bear are present but low-density. Pronghorn use open valleys, particularly in northern sections. Hunters should focus on the low ranges for sheep and mule deer, glass broad valleys for pronghorn, and hunt riparian corridors near the river for javelina.

Early and late season provide cooler conditions; midsummer heat severely limits comfort and success. Water planning is critical—access to the river or reservoirs may determine feasible hunting areas.