GMU 43A Unit 43A — Yuma
Colorado River bottoms and the Trigo/Chocolate ranges — a premier desert bighorn tag with sparse desert mule deer.
Lower Colorado River desert — Yuma region (BLM) · Last reviewed 2026-07-12
Area
944
sq mi
Public land
90%
approx.
Elevation
200–2,900
feet
Motorized
moderate
access
Overview
Unit 43A occupies the Lower Colorado River desert of far western Arizona, running along the river from roughly the Cibola/Palo Verde bottoms south toward Yuma. The rugged, barren desert ranges here — the Trigo and Chocolate mountains — hold desert bighorn sheep, the unit's marquee draw, while a thin population of desert mule deer works the washes and riparian edges near the river. This is low, hot, water-limited country that is overwhelmingly BLM public land, threaded by the green ribbon of the Colorado River and its refuges.
Terrain
Low Sonoran/Colorado desert: braided river bottoms and irrigated benches near the river rising abruptly into dry, rocky desert ranges (Trigo and Chocolate mountains) cut by sandy washes and rugged cliff country.
Cover: Cottonwood-willow and saltcedar along the Colorado River; creosote-bursage flats, ironwood, palo verde and cholla on the bajadas; sparse desert scrub and bare rock on the mountain faces.
Landmarks: Colorado River · Trigo Mountains (Trigo Mountains Wilderness) · Chocolate Mountains · Cibola National Wildlife Refuge · Imperial National Wildlife Refuge
Access
Overwhelmingly BLM public land, but access is defined by the river corridor. Cibola and Imperial National Wildlife Refuges allow hunting under refuge-specific rules — check refuge regulations before hunting them. Irrigated river-bottom farmland is private. The Trigo Mountains Wilderness is foot/horseback only (no motorized). State Trust parcels require an Arizona State Land recreation permit. Backcountry desert roads are primitive, sandy and unsigned — high-clearance 4WD and navigation are essential.
Managers: BLM, USFWS (Cibola & Imperial NWRs), AZ State Trust, Private (river-bottom farms)
Access points: US-95 corridor · Cibola NWR access roads · Martinez Lake / Imperial NWR area · primitive BLM desert roads off US-95
Species notes
Bighorn Sheep
limited trophyDesert bighorn in the Trigo and Chocolate ranges are the unit's flagship — a coveted, essentially once-in-a-lifetime tag with strong ram quality and near-certain success when drawn.
- →Glass rugged cliff faces, saddles and rincons of the Trigo Mountains at first and last light
- →Hunt on foot — the wilderness core is non-motorized rock-and-cliff country
- →Water sources and shaded north faces concentrate rams in heat
- →Long-range optics and patience over ground-pounding
Mule Deer
limited opportunityDesert mule deer occur at low density, concentrated near the Colorado River bottoms and the wash systems that drain the desert ranges. Success is modest (low-20s percent) — this is a spot-and-stalk grind, not a numbers hunt.
- →Focus the green river-bottom edges and mesquite/washes where deer water and browse
- →Glass the bajadas at dawn as deer move off feed
- →Hunt the transition between riparian cover and open desert
- →Expect low densities — cover ground and prioritize water
Pro tips
- →The bighorn tag is the prize — a rare draw; build points and hunt it hard on foot.
- →Anchor deer hunting to water and the green Colorado River edges, not the open flats.
- →The Trigo Mountains Wilderness is non-motorized — plan to backpack or day-hike into the sheep country.
- →Verify Cibola/Imperial NWR hunting rules separately — refuges carry their own regulations.
- →Overprepare for water and heat, and carry sand-capable recovery gear.
Watch out for
- !Extreme heat and near-total lack of natural water away from the Colorado River — carry ample water.
- !Cibola and Imperial National Wildlife Refuges have refuge-specific hunting rules and closures.
- !Trigo Mountains Wilderness is closed to motorized/mechanized travel.
- !Private irrigated farmland along the river — respect boundaries and get permission.
- !State Trust parcels require an Arizona State Land recreation permit.
- !Primitive sandy desert roads — 4WD, recovery gear and navigation are mandatory.
Logistics
Yuma is the full-service hub for fuel, supplies and lodging; Quartzsite and Blythe (CA) are smaller options to the north. Most hunting is dispersed camping on BLM desert. Carry far more water than you think you need, plus recovery gear, extra fuel and full navigation — this is remote, hot, unsigned desert.
Nearest towns: Yuma, Quartzsite, Blythe, CA, Cibola
Seasons & regulations
This page carries no season dates or regulations. Get current rules from the official Arizona sources:
Research sources: AZGFD GMU 43A · BLM Trigo Mountains Wilderness · Cibola National Wildlife Refuge (USFWS) · Imperial National Wildlife Refuge (USFWS)
FAQ
- How big is GMU 43A in Arizona?
- GMU 43A (Unit 43A — Yuma) covers about 944 square miles, ranging from roughly 200 to 2,900 feet in elevation. Area is computed from the unit boundary polygon.
- How much public land is in GMU 43A?
- Approximately 90% of the unit is public land. Primary managers: BLM, USFWS (Cibola & Imperial NWRs), AZ State Trust, Private (river-bottom farms). Always verify ownership boundaries on the ground.
- What species does the catalog list for GMU 43A?
- Bighorn Sheep, Mule Deer. For seasons, tags, and regulations, use the official Arizona agency resources linked on this page — this page carries no regulatory information.
Put GMU 43A on your map.
Boundary lines, public/private ownership, topo, and offline maps for this unit — in Baseline Maps, free for 14 days.