Colorado GMU 31 Mule Deer Hunting
Mesa, Garfield and Rio Blanco counties, northwest Colorado · 702 sq mi
Based on the EASIEST unit-wide buck or either-sex hunt code available to adult Colorado residents in the 2026 primary draw — the lowest preference-point tier that drew reliably. Private-land-only and Ranching for Wildlife hunts are excluded because neither is a unit-wide public-land opportunity — NOT because the public cannot draw them. A private-land-only license requires the hunter's own permission to hunt private ground; a Ranching for Wildlife license is valid on the participating ranches enrolled in that program. They are separate systems. Other weapons, seasons and nonresident applicants can require substantially more points. The band is a floor, not a target: even the easiest qualifying hunt here sits in that range.
What hunting GMU 31 is like
GMU 31 spans 702 square miles across Mesa, Garfield and Rio Blanco counties in Colorado's northwest region. Elevation ranges from 4,700 feet to 9,100 feet, with typical terrain around 6,900 feet. The unit's landscape is mixed, with substantial steep ground: 28% of the area is gentle, 38% moderate, 29% steep and 5% rugged. This mosaic of terrain types creates varied habitat and hunting conditions across the unit's breadth.
Public land available for hunting comprises roughly 57% of the unit—approximately 402 square miles managed by the BLM and Colorado Parks and Wildlife State Wildlife Areas. The remaining 43% is private land. Access to public ground depends on roads, trailheads and entry points that hunters will need to identify on the ground and in current access maps.
Mule deer occupy 60% of the unit as Winter Range and 60% as Summer Range. Winter Concentration covers 19% of the unit, indicating mule deer cluster on specific ground during winter months. Migration Corridors span 6% of the unit. Seasonal movement patterns mean that early hunts in September encounter deer in the velvet-shed and early fall transition phase, while archery in late September overlaps the same phenological window. Muzzleloader in mid-September also falls within the velvet-shed phase. Second Rifle in late October and Third Rifle in early-to-mid November span the transition from early fall migration and nocturnal buck phase into early pre-rut and the primary rut. Fourth Rifle in late November occurs during the primary rut. As the season progresses through fall, temperatures cool from September highs near 75°F to November highs near 47°F, with November snowfall averaging 2.5 inches.
The unit offers six seasons, five of which are open to public applicants: Archery (September 2–30, either-sex), Muzzleloader (September 12–20, buck), and three rifle seasons—Second Rifle (October 24–November 1, buck), Third Rifle (November 7–15, buck), and Fourth Rifle (November 18–22, buck). A sixth season is private-land-only and does not represent a public-land opportunity. Draw difficulty for the easiest unit-wide buck or either-sex hunt code available to adult Colorado residents is easy, often drawing at zero preference points. Overall hunter pressure on the unit is moderate.
Terrain & elevation
- Elevation
- 4,700–9,100 ft, typically around 6,900 ft
- Steepness
- Rugged — mean slope 19.8°
- Slope breakdown
- 28% gentle · 38% moderate · 29% steep · 5% rugged
- Ground you can count on
- ~402 sq mi
Land & access
About 57% of GMU 31 is public land a hunter can count on — BLM and State Wildlife Areas.
- BLM57%
- State Wildlife Area<1%
- Unclassified ownership<1%
- Private43%
Where mule deer live in the unit
Colorado Parks & Wildlife maps mule deer seasonal ranges statewide. This is how much of GMU 31 each range covers — the single best clue to whether mule deer are here in September, in November, or only passing through. The layers overlap, so they do not add to 100%.
- Overall Range100%the full extent of range CPW maps for mule deer — near 100% on most units, and not a statement about when mule deer are present
- Winter Range60%used in winter
- Summer Range60%used in summer
- Winter Concentration19%where mule deer bunch up in winter
- Migration Corridors6%movement between ranges, not residence
Mule Deer seasons & weapons (2026)
| Season | Dates | Tags offered |
|---|---|---|
| Archery | September 2 – September 30 | Either-sex |
| Muzzleloader | September 12 – September 20 | Buck |
| 2nd Rifle | October 24 – November 1 | Buck |
| 3rd Rifle | November 7 – November 15 | Buck |
| 4th Rifle | November 18 – November 22 | Buck |
| Private-land only | October 24 – November 15 | Buck |
Dates span every hunt code of that type in this unit and can differ by code. Confirm the current brochure with Colorado Parks & Wildlife before applying.
Fall weather
- September — highs around 75°F, lows around 47°F (mid-elevation normals)
- October — highs around 61°F, lows around 35°F, about 0.5 in of snow (mid-elevation normals)
- November — highs around 47°F, lows around 25°F, about 2.5 in of snow (mid-elevation normals)
GMU 31 mule deer hunting FAQ
How much public land can a hunter actually hunt in this unit?
Roughly 57% of GMU 31—approximately 402 square miles—is public land managed by the BLM and Colorado Parks and Wildlife State Wildlife Areas and is generally open to hunting. The remaining 43% is private. Public ownership does not guarantee access, however; hunters will need to locate roads, trailheads and entry points on current maps and scout the actual approach.
Does this unit require preference points to draw, or can a resident with zero points get in?
The easiest unit-wide buck or either-sex hunt code available to adult Colorado residents draws at zero preference points. Other weapons, seasons and nonresident applicants may require substantially more points, but a resident with no points has a realistic shot at the basic public-land opportunity.
Is this unit better for early-season or late-season hunting?
The unit offers five seasons spanning September through November. Early hunts (Archery and Muzzleloader in September) fall during the velvet-shed phase when deer are active in summer range. Later rifle seasons (late October through November) coincide with the transition into pre-rut and rut behavior, when buck movement and behavior shift. The choice depends on whether a hunter prefers early-season conditions or wants to hunt during the rut.
What is the terrain like for a hunter on foot?
The unit is mixed, with substantial steep ground: 28% gentle, 38% moderate, 29% steep and 5% rugged. Hunters will encounter rolling foothills, moderate slopes and genuinely steep country depending on where they access and hunt. The variety of terrain means some areas are more manageable for foot travel than others; scouting to identify the character of the ground nearest to public access will be important.
When do deer consolidate on winter ground during the hunt season?
Winter Concentration covers 19% of the unit. Third Rifle (November 7–15) and Fourth Rifle (November 18–22) both overlap the pre-rut and rut phases when deer shift toward winter range. Weather, snowfall and pressure all influence the timing and extent of that movement, which varies year to year.
Is this a crowded unit to hunt?
Overall hunter pressure is moderate. Draw difficulty is easy for the basic public-land hunts, meaning tags are available without high preference-point requirements—but an easy draw and actual crowding on the ground are separate matters. Hunters should plan to scout thoroughly and identify less-trafficked public ground if solitude is a priority.
Data sources & methodology
- Colorado Parks & Wildlife — Big Game hunting — seasons, weapons, hunt codes and license types
- CPW — Primary Draw rules — how preference points and the hybrid draw work
- CPW — Deer statistics, draw recap and Drawn Out At reports — the point levels behind the draw-difficulty bands
- CPW — Secondary Draw — licenses remaining after the primary draw
- CPW — Maps and GIS (Species Activity Mapping) — mule deer seasonal range
- CPW — State Trust Land Finder — which State Trust acreage is enrolled and open to public hunting
- Federal and state land-ownership datasets — land ownership and access
- NOAA climate normals — fall weather
Draw difficulty is a qualitative band, not published odds — the note under the summary above states exactly which hunt code it describes. Land shares are separate, non-overlapping categories: publicly owned is not the same as open to hunting, and State Trust Land is huntable only where CPW has enrolled it. Unit data last updated August 31, 2026.