Colorado GMU 20 Mule Deer Hunting
Larimer, Boulder and Weld counties, northeast Colorado · 1,207 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 20 is like
Colorado GMU 20 covers 1,207 square miles across Larimer, Boulder and Weld counties in the northeastern region. The unit spans from 4,800 feet to 14,200 feet in elevation, with terrain that is rolling to moderately steep: 45 percent of the area is gentle, 37 percent moderate, and 18 percent steep or rugged. This elevation range creates sharply different conditions between the plains, the foothills and the high country, and fall weather can push deer toward lower winter ranges.
Roughly 25 percent of the unit—about 305 square miles—is generally open to public hunting on National Forest, State Wildlife Areas and BLM land. National Park Service land covers approximately 22 percent and is closed to hunting. Private land accounts for 43 percent of the unit, and approximately 9 percent is unclassified ownership. Legal access is the primary constraint for hunters here: the open ground is scattered throughout the unit rather than contiguous, so a hunt requires identifying accessible routes and confirmed public property before heading into the field.
Mule deer occupy summer range across 79 percent of the unit, with that distribution contracting to 51 percent winter range as the season advances. Winter concentration areas—where deer cluster during cold months—cover 24 percent of the unit. Expect the seasonal shift from dispersed summer distribution to winter concentration to occur during the rifle seasons, with the pace and degree of movement varying by weather and snow. Early-season hunting occurs before significant consolidation; later rifle seasons coincide with increasing concentration on winter ground.
The unit offers six mule deer seasons: Archery (September 2–30, either-sex), Muzzleloader (September 12–20, doe or buck), 2nd Rifle (October 24–November 1, doe or buck), 3rd Rifle (November 7–15, doe or buck), 4th Rifle (November 18–22, doe or buck), and a private-land-only season. September hunting occurs with highs near 70 degrees Fahrenheit and no significant snowfall. October brings cooling to highs around 57 degrees and roughly 2 inches of snow. November continues to cool, with highs near 45 degrees and approximately 3.5 inches of snowfall. Draw difficulty is easy for the most accessible buck or either-sex hunt code available to adult Colorado residents. Hunter pressure on the unit is high.
Terrain & elevation
- Elevation
- 4,800–14,200 ft, typically around 7,500 ft
- Steepness
- Steep — mean slope 13.8°
- Slope breakdown
- 45% gentle · 37% moderate · 16% steep · 2% rugged
- Ground you can count on
- ~305 sq mi, plus ~7 sq mi of State Trust Land where access depends on enrollment
Land & access
About 25% of GMU 20 is public land a hunter can count on — National Forest, State Wildlife Areas and BLM. Another 22% is public but closed to hunting — National Park Service.
- National Forest25%
- State Wildlife Area<1%
- BLM<1%
- State Trust Land<1%
- National Park Service22%
- Unclassified ownership9%
- Private43%
“Ownership unclassified” means the source dataset does not record an owner for that acreage. It is not known to be public or private.
Where mule deer live in the unit
Colorado Parks & Wildlife maps mule deer seasonal ranges statewide. This is how much of GMU 20 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 Range79%used in summer
- Winter Range51%used in winter
- Winter Concentration24%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 | Doe, Buck |
| Private-land only | Dates vary by hunt code | Doe, 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 70°F, lows around 42°F (mid-elevation normals)
- October — highs around 57°F, lows around 32°F, about 2.3 in of snow (mid-elevation normals)
- November — highs around 45°F, lows around 23°F, about 3.5 in of snow (mid-elevation normals)
GMU 20 mule deer hunting FAQ
Can someone with no preference points draw a decent mule deer hunt here?
Yes. The easiest qualifying buck or either-sex code for an adult Colorado resident draws at zero points, making this a realistic option for any applicant. Other seasons or weapons may require preference points; check the current draw results for specific hunt codes.
How much of this unit can a public-land hunter actually access and hunt?
Approximately 25 percent of the unit—roughly 305 square miles—is open to public hunting across National Forest, State Wildlife Areas and BLM. The remaining 75 percent is either private, closed to hunting, or unclassified ownership. Public access depends entirely on knowing where open ground is located and how to reach it legally.
Is the terrain manageable for a hunter on foot?
Yes. Forty-five percent of the unit is gentle terrain, and 37 percent is moderate slope. The remaining 18 percent is steep or rugged, so most of the unit is walkable, though steeper pockets exist. Water access, weather, and distance matter more than slope in this case.
How does mule deer distribution change through the fall season?
Mule deer occupy summer range across 79 percent of the unit early in the season and consolidate to 51 percent winter range as temperatures drop. Twenty-four percent of the unit contains winter concentration areas where deer cluster. Expect movement toward winter ground during the rifle seasons, with timing and extent depending on weather and snow.
Which seasons fall in the mule deer rut?
The 3rd Rifle (November 7–15) and 4th Rifle (November 18–22) seasons bracket the primary rut period. The 2nd Rifle (October 24–November 1) occurs during early pre-rut staging. Archery and Muzzleloader seasons happen before the rut, during velvet shed and early fall transition.
How crowded is this unit relative to the difficulty of drawing?
Hunter pressure on the unit is high, but draw difficulty is easy—these are separate measures. An easy-to-draw tag near a population center can still receive heavy use. Expect significant other hunters in the field during all seasons.
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.