GMU 16B Unit 16B — Yuma
A small, draw-only desert bighorn sheep unit in the rugged ranges above the Colorado River
Lower Colorado River desert — western Arizona (BLM / Bill Williams River) · Last reviewed 2026-07-13
Area
129
sq mi
Public land
80%
approx.
Elevation
450–3,300
feet
Motorized
limited
access
Overview
Unit 16B is a compact desert unit straddling the lower Bill Williams River between Lake Havasu and Parker, dominated by the steep, rocky Buckskin and Rawhide mountains. It is best known as a premier desert bighorn sheep unit — tags are extremely limited and drawn once in a lifetime, and recent hunter success has been essentially 100%. This is a specialist's unit: rugged, remote, hot, and centered on a single marquee species rather than general deer or elk hunting.
Terrain
Low desert river corridor rising abruptly into precipitous, broken volcanic and granite mountain ranges with cliff bands, tinajas, and deep canyons — classic desert bighorn escape terrain.
Cover: Sonoran/Mojave transition desert: creosote, ocotillo, cholla, palo verde, ironwood and saguaro on the bajadas, with cottonwood-willow and tamarisk galleries along the Bill Williams River bottom.
Landmarks: Bill Williams River · Buckskin Mountains · Rawhide Mountains Wilderness · Bill Williams River National Wildlife Refuge · Lake Havasu
Access
Predominantly BLM land, including the Rawhide Mountains and Swansea wilderness areas (no motorized/mechanized travel). The Bill Williams River NWR is federal — check refuge-specific hunting rules before entering. Arizona State Trust parcels require a state recreation permit. Cross-country foot travel is the norm for sheep; the mountains have very few roads.
Managers: BLM, USFWS (Bill Williams River NWR), AZ State Trust, Private
Access points: Shea Road / Swansea Road off SR 95 near Bouse · Planet Ranch Road up the Bill Williams River · BLM backcountry routes from the Parker/Lake Havasu side
Species notes
Bighorn Sheep
common trophyThe signature species and the reason to draw this unit — desert bighorn hold in the Buckskin and Rawhide ranges above the river. Tags are minimal and once-in-a-lifetime, and success has run at or near 100% with quality rams available.
- →Glass from first light — pick apart cliff bands, saddles and shaded north faces with a spotting scope from long distance
- →Focus effort near reliable water (tinajas and the river corridor) in the heat, especially during the rut
- →Be prepared for very steep, loose rock and long stalks; sheep bed on ledges with escape terrain below
- →Hire or consult a bighorn-experienced guide given the once-in-a-lifetime nature of the tag
Pro tips
- →Treat this as a scouting-intensive hunt: spend days glassing the same slopes before your season to pattern individual rams
- →Water is the axis of everything in this desert — learn the tinajas and the river access points
- →Respect wilderness boundaries in the Rawhide and Swansea areas; no vehicles or bikes beyond the line
- →Confirm current Bill Williams River NWR access and any refuge closures before hunting the river corridor
Watch out for
- !Extreme heat and total lack of shade or water away from the river — dehydration is a real danger
- !Steep, loose cliff terrain with genuine fall exposure on sheep stalks
- !Arizona State Trust parcels require a recreation permit for legal access
- !Bill Williams River NWR has its own federal hunting restrictions distinct from surrounding BLM
- !Very limited roads and no services in the interior ranges
Logistics
Access via SR 95 between Parker and Lake Havasu City, then BLM and ranch roads into the ranges. Fuel, lodging and supplies in Parker and Lake Havasu City; carry far more water than you think you need — there is no reliable service in the backcountry and cell coverage drops off quickly away from the river.
Nearest towns: Parker, Lake Havasu City, Bouse, Quartzsite
Seasons & regulations
This page carries no season dates or regulations. Get current rules from the official Arizona sources:
Research sources: AZGFD Game Management Unit information · BLM Arizona — Rawhide Mountains & Swansea Wilderness · USFWS Bill Williams River National Wildlife Refuge
FAQ
- How big is GMU 16B in Arizona?
- GMU 16B (Unit 16B — Yuma) covers about 129 square miles, ranging from roughly 450 to 3,300 feet in elevation. Area is computed from the unit boundary polygon.
- How much public land is in GMU 16B?
- Approximately 80% of the unit is public land. Primary managers: BLM, USFWS (Bill Williams River NWR), AZ State Trust, Private. Always verify ownership boundaries on the ground.
- What species does the catalog list for GMU 16B?
- Bighorn Sheep. For seasons, tags, and regulations, use the official Arizona agency resources linked on this page — this page carries no regulatory information.
Put GMU 16B on your map.
Boundary lines, public/private ownership, topo, and offline maps for this unit — in Baseline Maps, free for 14 days.