Colorado GMU 421 Mule Deer Hunting
Mesa and Garfield counties, northwest Colorado · 541 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 421 is like
Unit 421 sprawls across 541 square miles of northwestern Colorado in Mesa and Garfield counties, rolling terrain with some steeper breaks. Elevations range from 4,800 feet to 11,200 feet, with a typical elevation around 8,300 feet. The terrain breaks down to 51 percent gentle slopes, 40 percent moderate slopes, 9 percent steep terrain, and 1 percent rugged country by area. This mix of rolling and broken ground offers varying hunting conditions from season to season as hunters pursue mule deer across the unit.
Public land covers approximately 65 percent of the unit—about 352 square miles where a hunter can count on access. The National Forest holds the bulk of this public ground at 54 percent of the unit, with BLM contributing 10 percent and State Wildlife Areas making up less than 1 percent. Private land accounts for approximately 34 percent of the unit. The remaining fraction is unclassified. The substantial public acreage provides genuine opportunity, though roads, trailheads, and seasonal closures will dictate any specific approach.
Mule deer in Unit 421 concentrate seasonally across mapped ranges. Summer Range covers 84 percent of the unit, indicating broad distribution during the warmer months. Winter Range drops to 23 percent coverage, with Winter Concentration marking 11 percent of the unit where mule deer cluster as temperatures cool. This shift in coverage through the fall suggests hunters should expect animals to concentrate on winter ground as the season advances, though the timing and extent depend on weather and snow. Migration Corridors are not mapped here.
The unit offers six seasons across both archery and rifle. Five are open to public applicants: Archery runs September 2–30 as either-sex; Muzzleloader runs September 12–20 as doe or buck; three rifle seasons span October 24 through November 22, with the 2nd Rifle (October 24–November 1) and 3rd Rifle (November 7–15) both as doe or buck, and the 4th Rifle (November 18–22) as buck only. Early seasons overlap the Velvet Shed phase when bucks have recently shed antler velvet, while October and early November hunts encounter Early Fall Migration and Early Pre-Rut behavior; late November coincides with the Primary Rut. A sixth season, October 24–November 15 as buck only, is private-land only. Overall hunter pressure is high, and draw difficulty is moderate, meaning the easiest qualifying either-sex hunt for an adult Colorado resident draws at 1–2 preference points.
Terrain & elevation
- Elevation
- 4,800–11,200 ft, typically around 8,300 ft
- Steepness
- Moderate — mean slope 12°
- Slope breakdown
- 51% gentle · 40% moderate · 9% steep · 1% rugged
- Ground you can count on
- ~352 sq mi
Land & access
About 65% of GMU 421 is public land a hunter can count on — National Forest, BLM and State Wildlife Areas.
- National Forest54%
- BLM10%
- State Wildlife Area<1%
- Unclassified ownership<1%
- Private34%
Where mule deer live in the unit
Colorado Parks & Wildlife maps mule deer seasonal ranges statewide. This is how much of GMU 421 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 Range84%used in summer
- Winter Range23%used in winter
- Winter Concentration11%where mule deer bunch up in winter
- Migration Corridors<1%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 | 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 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 68°F, lows around 42°F (mid-elevation normals)
- October — highs around 55°F, lows around 32°F, about 1.7 in of snow (mid-elevation normals)
- November — highs around 43°F, lows around 21°F, about 8.7 in of snow (mid-elevation normals)
GMU 421 mule deer hunting FAQ
Can someone with no preference points draw a public hunt in Unit 421?
Yes. The easiest unit-wide either-sex hunt draws at 1–2 preference points, making it accessible to residents starting from zero points. Other seasons and weapons may require more points, and nonresidents face a different draw standard entirely.
Is Unit 421 realistic for a public-land hunter with limited time?
The unit spans 541 square miles with 352 square miles of public land managed by the National Forest, BLM, and State Wildlife Areas. Terrain is mostly rolling to moderate, but entry points and accessibility depend on roads and trailheads—the public ownership alone does not guarantee straightforward access. A hunter should scout approaches before applying.
Does the unit fish better early or late in the season?
The unit is for mule deer, not fish. The earliest archery season (September 2–30) finds bucks in Velvet Shed phase with recent antler activity. Later rifle seasons—especially the 3rd Rifle (November 7–15) and 4th Rifle (November 18–22)—coincide with Early Pre-Rut and Primary Rut behavior, when buck activity typically increases.
When should I expect mule deer to move toward winter ground?
Winter Range covers only 23 percent of the unit compared to 84 percent Summer Range, suggesting mule deer concentrate on winter ground as the season advances. This shift typically accelerates through November as temperatures drop—the month sees average snowfall of 8.7 inches at mid-elevation—but timing varies with actual weather conditions.
How much colder does it get through the fall?
September highs average around 68°F at mid-elevation, dropping to October highs near 55°F and November highs around 43°F. November also brings roughly 8.7 inches of snowfall on average, creating substantially harder hunting conditions late in the season.
What does the draw-difficulty band cover and what does it not?
The Moderate rating describes the easiest unit-wide buck or either-sex hunt for an adult Colorado resident—currently the archery or muzzleloader seasons at 1–2 points. It does not apply to other rifle seasons, nonresidents, or private-land-only hunts, all of which may require substantially more preference points.
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.