Colorado GMU 23 Mule Deer Hunting
Rio Blanco and Garfield counties, northwest Colorado · 423 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 23 is like
Unit 23 sprawls across 423 square miles in Rio Blanco and Garfield counties in the northwest region, rolling to moderately steep country that climbs from 6,100 feet to 10,100 feet. The terrain breaks down to 47% gentle slopes, 38% moderate, and 15% steep, making it navigable for hunters on foot across much of its extent. Early fall temperatures run mild—September highs near 72°F and lows in the low 40s—but cold sets in by November, when highs drop to the mid-40s and snow begins to accumulate, averaging six inches of monthly snowfall by mid-autumn.
Public land covers roughly 45% of the unit, or about 189 square miles, managed by the U.S. Forest Service, Bureau of Land Management, and State Wildlife Areas. Private land makes up the remaining 55%. The public ground is generally open to hunting, though roads, trailheads, and private inholdings within and around it shape where a hunter can actually reach. The private share is substantial and worth accounting for when planning access.
Mule deer occupy the entire unit across all mapped seasonal ranges, with both summer range and winter range covering 100% of the mapped area. However, mule deer concentrate heavily in particular zones—19% of the unit falls within winter concentration areas where deer cluster during the cold months. Migration corridors cover 44% of the unit, indicating that movement across the landscape is significant through fall; a hunter should expect deer distribution to shift as the season progresses and animals migrate toward and concentrate on winter ground, though the timing and extent of that movement vary with weather and snow.
The unit offers seven seasons total, five of which are open to public applicants. Archery runs September 2–30 for either-sex hunting during the velvet-shed phase. Muzzleloader follows September 12–20 for doe and buck. Three rifle seasons are available: the second rifle runs October 24–November 1, the third rifle November 7–15, and the fourth rifle November 18–22 (buck only). The second and third rifle seasons span the early fall migration and early pre-rut phases; the third and fourth rifle seasons overlap the rut itself. A private-land-only season runs October 24–November 22, and a Ranching for Wildlife opportunity is also offered. Draw difficulty for the easiest unit-wide public-land buck or either-sex code is easy, often requiring zero preference points for an adult Colorado resident.
Terrain & elevation
- Elevation
- 6,100–10,100 ft, typically around 7,800 ft
- Steepness
- Steep — mean slope 13.3°
- Slope breakdown
- 47% gentle · 38% moderate · 15% steep · 0% rugged
- Ground you can count on
- ~189 sq mi
Habitat & cover
What actually grows here, by elevation. Each band adds to 100% on its own — these are shares of that band, not of GMU 23.
Lower elevations
- Sagebrush47%
- Other cover23%
- Aspen18%
- Conifer10%
- Riparian2%
Mid elevations
- Aspen66%
- Sagebrush23%
- Conifer9%
- Other cover1%
Higher elevations
- Aspen59%
- Conifer23%
- Sagebrush16%
- Grass and meadow1%
Cover classes from the USGS National Land Cover Database, split into elevation bands. “Other cover” is the remainder of the classification — bare ground, water, agriculture and developed land — and is left unnamed rather than guessed at.
Land & access
About 45% of GMU 23 is public land a hunter can count on — National Forest, BLM and State Wildlife Areas.
- National Forest32%
- BLM8%
- State Wildlife Area5%
- Private55%
Where mule deer live in the unit
Colorado Parks & Wildlife maps mule deer seasonal ranges statewide. This is how much of GMU 23 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
- Summer Range100%used in summer
- Winter Range52%used in winter
- Migration Corridors44%movement between ranges, not residence
- Winter Concentration19%where mule deer bunch up in winter
Mule Deer seasons & weapons (2026)
| Season | Dates | Tags offered |
|---|---|---|
| Archery | September 2 – September 30 | Either-sex |
| Muzzleloader | September 12 – September 20 | Doe, Buck |
| 2nd Rifle | October 24 – November 1 | Doe, Buck |
| 3rd Rifle | November 7 – November 15 | Doe, Buck |
| 4th Rifle | November 18 – November 22 | Buck |
| Private-land only | October 24 – November 22 | Either-sex |
| Ranching for Wildlife | Dates vary by hunt code | Either-sex, Doe |
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 72°F, lows around 43°F (mid-elevation normals)
- October — highs around 59°F, lows around 32°F, about 1.2 in of snow (mid-elevation normals)
- November — highs around 45°F, lows around 22°F, about 6.2 in of snow (mid-elevation normals)
GMU 23 mule deer hunting FAQ
Is Unit 23 realistic for a hunter with no preference points?
Yes. The easiest unit-wide public-land buck or either-sex hunt code here draws reliably at zero points for adult Colorado residents in the primary draw. Applicants with no points do sometimes draw, and the secondary draw in June and the leftover list after the primary draw offer additional opportunities with no preference points required.
How much public land can a hunter actually access here?
The unit contains roughly 189 square miles of generally open public land managed by the U.S. Forest Service, Bureau of Land Management, and State Wildlife Areas—about 45% of the unit's total. Private land accounts for 55%, and specific road access, trailheads, and private inholdings will dictate what portions a hunter can reach; public ownership alone does not guarantee straightforward entry.
Does the terrain here require serious mountaineering skills?
No. The unit is rolling to moderately steep, with 47% gentle slopes and 38% moderate slopes; only 15% is steep. Hunters on foot can navigate much of the ground, though the elevation span from 6,100 to 10,100 feet means some climbs are unavoidable.
Where should a hunter focus effort early versus late in the fall?
Archery and muzzleloader in September fall in the velvet-shed phase, when deer are still settling into summer patterns. Rifle seasons October through November span the early fall migration and rut phases, when deer movement and concentration on winter ground accelerates. A hunter should expect deer distribution to shift toward winter concentration zones as the season progresses, though the pace depends on weather and snow.
Is this unit crowded with other hunters?
Overall hunter pressure in the unit is low. Draw difficulty is easy, meaning tags are relatively available, but these are different measures—an easy draw does not automatically mean heavy pressure on the ground. Actual crowding depends on individual hunter choices and the season.
Where do mule deer cluster on this unit?
Winter concentration areas cover 19% of the unit but the facts do not specify their location by elevation, aspect, or geographic position—only that they exist and form focus areas when cold weather arrives. A hunter should consult maps and current conditions to pinpoint where those zones lie in relation to public access.
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
- USGS / MRLC — National Land Cover Database — habitat and cover classes by elevation band
- 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
- USGS PAD-US — Protected Areas Database of the United States — land ownership and access
- Daymet daily climate, 1991–2020 (Oak Ridge National Laboratory) — 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 September 24, 2026.