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
GMU 23 spans 423 square miles across Rio Blanco and Garfield counties in northwest Colorado, rising from 6,100 feet to 10,100 feet with typical elevations around 7,800 feet. The terrain is rolling to moderately steep, with 47 percent gentle slopes, 38 percent moderate slopes, and 15 percent steep terrain. The unit's mean slope of 13.3 degrees places it in the steep band overall, but the landscape allows for a mix of easier and more demanding country.
Approximately 45 percent of the unit, roughly 189 square miles, is generally open to public hunting on National Forest, BLM, and State Wildlife Areas land. The remainder, approximately 55 percent, is private. This public-land split means nearly half the unit is available to hunters without securing private permission, though accessing specific areas still depends on roads, trailheads, and the location of inholdings.
Mule deer occupy the entire unit across their overall range, which extends through summer range and winter range mapped across the area. Winter concentration habitat covers 19 percent of the unit, where mule deer cluster during the coldest months. Migration corridors span 44 percent of the unit, and as temperatures cool and snow accumulates through fall, hunters should expect mule deer movement toward areas where they concentrate for winter. Winter range covers 52 percent of the unit, providing year-round sanctuary as the season deepens into late fall and early winter.
GMU 23 offers seven seasons total: archery from September 2 to September 30 for either-sex; muzzleloader from September 12 to September 20 for doe or buck; three rifle seasons—the 2nd Rifle from October 24 to November 1, 3rd Rifle from November 7 to November 15, and 4th Rifle from November 18 to November 22, all for doe or buck except the 4th Rifle, which is buck-only; a private-land-only season from October 24 to November 22 for either-sex; and a Ranching for Wildlife opportunity with no published dates. The archery and muzzleloader seasons fall during the velvet-shed and early fall transition phase, when bucks have shed their antlers' velvet and behavior begins to shift. The 2nd Rifle overlaps the early fall migration and nocturnal buck phase. The 3rd Rifle spans the early pre-rut and primary rut periods, when buck activity intensifies. The 4th Rifle occurs during the primary rut. Draw difficulty is easy, often requiring zero preference points for the easiest qualifying unit-wide either-sex or buck code available to adult Colorado residents. Extreme hunter pressure characterizes this unit despite the favorable draw odds.
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
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
Can a hunter with no preference points draw one of these tags?
Yes. The 2026 draw difficulty for GMU 23 is easy, and the easiest qualifying unit-wide either-sex or buck code has drawn reliably at zero points for adult Colorado residents. However, this band describes only the lowest preference-point tier that drew consistently and is not a guarantee; other seasons, weapons, and nonresident applicants can require substantially more points.
Is this unit realistic for a hunter planning to work public land only?
Public land makes up roughly 45 percent of the unit, or about 189 square miles, distributed across National Forest, BLM, and State Wildlife Areas. Whether that represents enough huntable ground depends on the location of roads, trailheads, and private inholdings, which determine actual access. A hunter should scout the unit's access points before applying.
When should a hunter expect peak buck activity and what does that mean for season choice?
The 4th Rifle season from November 18 to November 22 falls squarely in the primary rut, when buck activity and visibility peak. The 3rd Rifle from November 7 to November 15 spans the transition into the rut and offers similar opportunities. Archery and muzzleloader in September occur during the velvet-shed phase, when bucks are visible but behavior differs from the rut.
How much does weather change across the fall hunt season?
September highs average around 72°F and lows around 43°F with negligible snow. October cools slightly, with highs near 59°F, lows near 32°F, and about 1.2 inches of snow. November drops significantly, with highs near 45°F, lows near 22°F, and roughly 6.2 inches of snow, making conditions progressively more challenging.
Where do mule deer concentrate, and does that change through the season?
Winter concentration habitat covers 19 percent of the unit where mule deer cluster during the coldest months. As the season progresses from fall into early winter and temperatures drop, mule deer shift their presence toward this concentrated ground and the broader 52 percent of the unit mapped as winter range. The timing and extent of this movement vary with weather and snow conditions.
Is extreme hunter pressure the same as drawing being hard to do?
No. This unit draws at zero points for the easiest qualifying tag, but it experiences extreme hunter pressure from the large number of tags issued and hunters on the ground. An easy draw and crowded conditions can happen together, especially on public land near population centers and main roads.
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.