Colorado GMU 66 Mule Deer Hunting
Gunnison, Hinsdale and Saguache counties, southwest Colorado · 899 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 66 is like
GMU 66 spans 899 square miles across the high country of southwest Colorado, covering portions of Gunnison, Hinsdale and Saguache counties. The unit encompasses low elevations around 7,200 feet and climbs to peaks above 14,300 feet, with typical terrain at 10,200 feet. The landscape is mixed, with substantial steep ground: roughly a third of the unit is gentle, 42 percent moderate terrain, and a quarter is steep, with the steepest sections making up 2 percent. This elevation span and terrain variation create distinct seasonal ranges for mule deer across the fall hunt.
Public hunting ground comprises about 80 percent of the unit and is distributed among three major landholders: 45 percent BLM, 35 percent National Forest, and a small fraction as State Wildlife Area. The remaining 20 percent is private land. This public-land share gives hunters substantial terrain to explore, though access and approach still depend on roads, trailheads and seasonal conditions specific to each drainage and aspect.
Mule deer occupy summer range across 99 percent of the unit through August. As fall progresses, the mapping indicates that hunters should expect deer to concentrate on winter range covering 31 percent of the unit, with 21 percent forming a winter concentration zone where animals cluster more densely. Migration corridors covering 34 percent of the unit mark the movement routes between seasons. The timing and extent of this seasonal shift vary with weather and snow, but the broad transition from summer across migration ground to winter concentration typically proceeds through October and November.
The unit offers five seasons across different weapons. Archery runs September 2–30 for bucks, coinciding with the velvet-shed and early fall transition phase when bucks are shedding velvet and beginning to move. Muzzleloader also opens in this window, running September 12–20. Three rifle seasons follow: the 2nd Rifle from October 24–November 1, the 3rd Rifle from November 7–15, and the 4th Rifle from November 18–22. The 2nd Rifle spans the early fall migration phase into early pre-rut staging; the 3rd Rifle crosses into and through the primary rut; and the 4th Rifle occurs during the primary rut. All rifle seasons offer both doe and buck opportunity except the 4th, which is buck-only. Hunter pressure across the unit is low, and the draw for the easiest unit-wide buck or either-sex hunt available to adult Colorado residents typically requires 1–2 preference points, though premium seasons within the unit demand substantially more.
Terrain & elevation
- Elevation
- 7,200–14,300 ft, typically around 10,200 ft
- Steepness
- Steep — mean slope 17.4°
- Slope breakdown
- 32% gentle · 42% moderate · 24% steep · 2% rugged
- Ground you can count on
- ~719 sq mi
Land & access
About 80% of GMU 66 is public land a hunter can count on — BLM, National Forest and State Wildlife Areas.
- BLM45%
- National Forest35%
- State Wildlife Area<1%
- Private20%
Where mule deer live in the unit
Colorado Parks & Wildlife maps mule deer seasonal ranges statewide. This is how much of GMU 66 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 Range99%used in summer
- Migration Corridors34%movement between ranges, not residence
- Winter Range31%used in winter
- Winter Concentration21%where mule deer bunch up in winter
Mule Deer seasons & weapons (2026)
| Season | Dates | Tags offered |
|---|---|---|
| Archery | September 2 – September 30 | Buck |
| Muzzleloader | September 12 – September 20 | Buck |
| 2nd Rifle | October 24 – November 1 | Doe, Buck |
| 3rd Rifle | November 7 – November 15 | Doe, Buck |
| 4th Rifle | November 18 – November 22 | 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 63°F, lows around 36°F (mid-elevation normals)
- October — highs around 53°F, lows around 27°F, about 3.2 in of snow (mid-elevation normals)
- November — highs around 41°F, lows around 16°F, about 12 in of snow (mid-elevation normals)
GMU 66 mule deer hunting FAQ
Is this unit huntable for someone with no preference points?
Yes. The easiest unit-wide buck or either-sex hunt available to adult residents draws at 1–2 preference points. An applicant with zero points will not draw this tier, but some seasons or codes within the unit may draw at zero. Check the current draw statistics for specific season codes to confirm which hunts are reachable without points.
Does this unit stay open to public access through the season?
Public land covers about 80 percent of the unit across BLM, National Forest, and State Wildlife Area holdings. Seasonal road closures, weather, snow accumulation, and private inholdings all affect where hunters can actually go as fall progresses. Verify current access conditions for specific drainages before the season.
Which seasons fall during the rut?
The 3rd Rifle (November 7–15) crosses into and through the primary rut, and the 4th Rifle (November 18–22) occurs entirely within the primary rut. The earlier seasons—archery in September and muzzleloader in mid-September—occur during velvet shed and early fall transition, well before the rut begins in mid-November.
Where should a hunter focus effort early versus late in the season?
Summer range covers 99 percent of the unit in early season, so deer are widely distributed in September. As fall advances through October and November, expect deer to shift toward winter range (31 percent of the unit) and especially the winter concentration zone (21 percent) where animals cluster. The timing and extent of this shift depend on weather and snow accumulation.
Is the terrain manageable for a hunter on foot?
The unit is mixed terrain with roughly a third gentle ground and 42 percent moderate slopes, but a quarter is steep and 2 percent is rugged. A hunter comfortable with sustained moderate climbing and steep sections can cover the unit, but the steeper portions will challenge those seeking easy foot access. Elevation at mid-season runs around 10,200 feet, bringing thin air and cold nights.
What should a hunter expect weather-wise across the fall?
September highs average near 63°F with cool nights around 36°F and minimal snowfall. October cools further, with highs near 53°F and average snowfall of about 3.2 inches. November turns harsh, with highs dropping to around 41°F and average snowfall of about 12 inches. The season progresses from warm mornings in September to November conditions that can dump significant snow quickly.
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.