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Colorado GMU 421 mule deer: terrain, access and seasons

Unit 421's terrain, access, seasons and CPW mule deer figures, with Conditions rebuilt nightly.

By Bryson, co-founder Updated

2026 season

Second rifle Oct 24–Nov 1

Every section below follows this season.

Decide

The season's licenses, draw results and harvest figures.

At a glance

Second rifle runs Oct 24–Nov 1, 2026; CPW's 2024 harvest survey put success at 50% for 441 hunters.

Size
541 sq mi
CPW unit boundary, 2025
Counties
Mesa, Garfield
Elevation
4,780–11,240 ft
USGS 3DEP, 2026-10-19
Huntable public land
66%
COMaP, 2026-10-12
Second rifle license, 2026
Draw buck, doe
CPW 2026 big game brochure. Colorado has no OTC mule deer license
Success
50%
CPW harvest survey, 2024
Hunters
441
CPW harvest survey, 2024
Hunter-days per sq mi
3.4
CPW, 2024
Road miles, any vehicle
205 mi
MVUM + CDOT, open on the Oct 24 opener
Median Habitat Score
2 of 5
Ranks 77th of 156 for second rifle. Glassline, v4, 2026-10-19
Snow now
5 in
Deepest at Park Reservoir SNOTEL, 2026-10-20

In short

A mid-elevation, mostly timbered draw-only unit with more hunters than in 2022. Most of Unit 421 sits between 7,000 and 10,000 feet, with conifer and aspen in roughly equal measure, then shrubland. About two-thirds of the unit is huntable public land, and about a tenth of that ground is more than an hour and a half on foot from a drivable road. CPW's survey counted 934 hunters across all seasons in 2024, up from 775 in 2022, while second rifle success rose from 46% to 50%. Every license here is drawn, as for all Colorado mule deer.

Licenses and draw

Second rifle in Unit 421, 2026: a draw buck license (D-M-041-O2-R) and a draw doe license (D-F-041-O2-R).

  • D-M-041-O2-R buck, draw 2026 draw: residents drawn out at 0 points; nonresidents drawn out at 1 point
  • D-F-041-O2-R doe, draw 2026 draw: residents drawn out at 4 points; nonresidents none drawn

CPW 2026 big game brochure; CPW primary-draw recap and drawn-out-at reports, 2024–2026, adult licenses. Every year of draw results is under Hunt codes and draw results.

Plan

The map, Conditions, access, hunt codes and draw results for the season, and what the research says.

Map

The interactive map (public land by manager, roads by vehicle class, burns, trailheads, SNOTEL stations, terrain and CPW's mapped ranges) needs JavaScript. The outline shows where Unit 421 sits among its neighbors.

42 52 41 411 521 421

Public data only. The plan lives in the app. Map sources

Conditions

As of Oct 21: 5 in of snow at Park Reservoir SNOTEL, the deepest reading near the unit; extreme drought (D3) on the US Drought Monitor over 39% of the unit.

Rebuilt nightly; sources at the end of the page.

Item Value Data
Snow (SNOTEL) Mesa Lakes (10,160 ft): 0 in deep, SWE 0.3 inPark Reservoir (9,990 ft, 1.6 mi out): 5 in deep, SWE 1.8 inOverland Res. (9,890 ft, 2 mi out): 0 in deep, SWE 0.1 in 2026-10-20 2026-10-20
Drought D3, Extreme droughtShare of the unit: D0 or worse 100% · D1 or worse 100% · D2 or worse 100% · D3 or worse 39% USDM 2026-10-13 USDM 2026-10-13
Greenness vs normal, Sep 14–29 94% of the September normal (2014–2023), MODIS 16-day composite 2026-09-29 2026-09-29

7-day forecast

NWS 7-day gridpoint forecast for 8,000–9,000 ft and 10,000–11,000 ft, issued Oct 21; the second rifle opener, Oct 24, is marked; no front named in the NWS discussion for the 7 days.

8,000–9,000 ft NWS GJT gridpoint 120,105, issued 2026-10-21. Gusts and lows: gridpoint only. No front named in the NWS discussion for the 7 days.
Wed 10/21 Thu 10/22 Fri 10/23 Sat 10/24 Opener Sun 10/25 Mon 10/26 Tue 10/27
High / low 53° 42°54° 47°51° 40°50° 38°48° 39°49° 38°50° 38°
Precip 0.2 in0.8 in0.1 in0.1 in0.1 in0 in0 in
Snow 0 in0 in0 in0 in0 in0 in0 in
Gusts 14 mph21 mph25 mph10 mph9 mph8 mph12 mph
10,000–11,000 ft NWS GJT gridpoint 120,103, issued 2026-10-21. Gusts and lows: gridpoint only. No front named in the NWS discussion for the 7 days.
Wed 10/21 Thu 10/22 Fri 10/23 Sat 10/24 Opener Sun 10/25 Mon 10/26 Tue 10/27
High / low 45° 37°46° 41°42° 32°41° 31°40° 31°41° 30°41° 30°
Precip 0.3 in1.1 in0.2 in0.2 in0.1 in0 in0 in
Snow 0 in0 in0 in0.2 in0.1 in0 in0 in
Gusts 15 mph23 mph31 mph10 mph9 mph8 mph10 mph

Access

Unit 421 has 18 trailheads and about 205 miles of road any vehicle may drive on the second rifle opener, plus 112 more that need high clearance. About half of the huntable public ground is within a 30-minute walk of a drivable road, and about a tenth is more than an hour and a half away.

Trailheads
18
COTREX, computed 2026-10-19
Road miles open, second rifle opener Oct 24–Nov 1, by the smallest vehicle allowed. MVUM plus county and state roads.
Vehicle Miles
Any vehicle
205 mi
High clearance
112 mi
4x4
0 mi
Walking time from a drivable road Share of huntable public ground by foot time from the nearest drivable road. Foot time at a standard pace on Glassline's travel model (slope, vegetation, trails), from the nearest highway, road a high-clearance vehicle can drive, or trailhead, with every road open.
Walking time Share
Within 30 min
47.8%
30–60 min
26.5%
60–90 min
14.9%
Over 90 min
10.8%

Hunt codes and draw results

2 hunt codes for second rifle, 2026, with CPW's primary-draw results for 2024–2026.

Hunt code Year Licenses Residents Nonresidents
1st-choice applicants Drawn Drawn out at 1st-choice applicants Drawn Drawn out at
D-M-041-O2-R buck 2024 1,000 609 542 0 points 449 198 0 points
2025 600 688 322 0 points 418 114 1 point
2026 600 575 324 0 points 417 116 1 point
D-F-041-O2-R doe 2024 10 119 6 5 points 4 0 None Drawn
2025 10 122 6 5 points 3 0 None Drawn
2026 10 106 5 4 points 2 0 None Drawn

Hunt codes from the CPW 2026 big game brochure. A code valid in several units counts every hunter in all of them.

Draw results are CPW's primary-draw recap and drawn-out-at reports, 2024–2026, adult licenses. "Drawn out at" is the lowest preference-point level that drew a license; "Leftover" means licenses remained after the draw. A code valid in several units counts every applicant for all of them. Source: CPW draw reports, 2024–2026.

What the research says for this season

Findings from published studies and agency work, as tendencies. They describe how mule deer have behaved where they were studied, not where they are in Unit 421.

  • In a south-central Wyoming herd, mature bucks moved away from motorized routes into roadless cover during a rifle season while does stayed on their usual forage, and hunting barely changed when deer migrated.

    Rodgers et al., 2021 Single study

  • In Colorado's Gunnison Basin, GPS-collared mule deer made their fall migration from late October into early November, along corridors averaging about 17 miles.

    Kauffman et al., 2024 Single study

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POIs are terrain candidates — places worth checking, not animal locations.

Reference

Terrain, the multi-year numbers, neighbors and sources. Each opens in place.

Terrain and habitat

4,780–11,240 ft; conifer 23.9% and aspen 23.5%; no mapped burns since 2020.

Unit-wide figures, computed 2026-10-19.

Elevation Acres per 1,000 ft band. USGS 3DEP.
  1. 4k–5k ft 150 ac
  2. 5k–6k ft 25,210 ac
  3. 6k–7k ft 52,240 ac
  4. 7k–8k ft 73,130 ac
  5. 8k–9k ft 68,990 ac
  6. 9k–10k ft 61,460 ac
  7. 10k–11k ft 62,780 ac
  8. 11k–12k ft 180 ac
Table view
BandAcres
4,000–5,000 ft150 ac
5,000–6,000 ft25,210 ac
6,000–7,000 ft52,240 ac
7,000–8,000 ft73,130 ac
8,000–9,000 ft68,990 ac
9,000–10,000 ft61,460 ac
10,000–11,000 ft62,780 ac
11,000–12,000 ft180 ac
Slope Share of the unit per slope class.
  1. Under 5° 22.6%
  2. 5–15° 44.8%
  3. 15–25° 21.2%
  4. 25–35° 9%
  5. 35°+ 2.4%
Table view
Slope classShare
Flat (under 5°)22.6%
Gentle (5–15°)44.8%
Moderate (15–25°)21.2%
Steep (25–35°)9%
Very steep (35° and up)2.4%
Aspect Share of non-flat ground facing each way.
  1. N 13.9%
  2. NE 12.3%
  3. E 10.9%
  4. SE 9.3%
  5. S 9.5%
  6. SW 12.2%
  7. W 16.5%
  8. NW 15.4%
Table view
AspectShare
North13.9%
Northeast12.3%
East10.9%
Southeast9.3%
South9.5%
Southwest12.2%
West16.5%
Northwest15.4%
Vegetation LF2024 existing vegetation, groups of 1% or more.
  1. Conifer 23.9%
  2. Aspen 23.5%
  3. Shrubland 20.7%
  4. Pinyon-juniper 14.9%
  5. Grass & meadow 5.7%
  6. Riparian & wetland 4.1%
  7. Farmland 3.7%
  8. Rock & scree 1.6%
  9. Developed 1.3%
Table view
Vegetation groupShare
Conifer23.9%
Aspen23.5%
Shrubland20.7%
Pinyon-juniper14.9%
Grass & meadow5.7%
Riparian & wetland4.1%
Farmland3.7%
Rock & scree1.6%
Developed1.3%
Item Value Data
Burns No burned acres in the unit since 2020 NIFC NIFC
Openings in timber 2,402 openings of 1–40 ac, from lidar covering 100% of the unit 2026-10-19 2026-10-19
Habitat Score, second rifle Share of 226,200 ac of huntable public ground in each score band. Median 2. Scoring v4, computed 2026-10-19.
Table view
ScoreShare of scored ground
0–0.50%
0.5–14.1%
1–1.513.8%
1.5–233%
2–2.529.3%
2.5–315.5%
3–3.54.2%
3.5–40%
4–4.50%
4.5–50%

Glassline's Habitat Score grades terrain and habitat for the season on food, water, breeding and shelter. Shown here as one distribution for the whole unit, never a map: it grades ground, not animal locations.

The numbers

CPW harvest estimates 2022–2024 for the chosen season and all seasons, the North Grand Mesa herd (D-12) estimate for 2025 and hunter density, 2024.

Second rifle success rose from 46% to 50% between 2022 and 2024, while the season's hunters rose by about a third. Across all seasons, hunters rose by about a fifth between 2022 and 2024. Unit 421 is one of 3 units in CPW's North Grand Mesa mule deer herd (DAU D-12), estimated at about 19,000 mule deer after the 2025 hunt, with 29 bucks per 100 does.

Hunters, harvest and success
Season Year Hunters Harvest Success
Second rifle 2022 325 149 46%
2023 396 194 49%
2024 441 218 50%
All seasons 2022 775 341 44%
2023 806 349 43%
2024 934 406 43%

CPW deer harvest reports, 2022–2024. A dash: not reported.

Item Value Data
Hunter density 9 hunter-days per sq mi, all seasons CPW 2024 CPW 2024
Herd estimate (North Grand Mesa, D-12) 19,030 post-hunt · 14,120 in 2019 CPW 2025 CPW 2025
Buck:doe ratio 29 bucks per 100 does CPW 2025 CPW 2025

CPW harvest figures are survey estimates, not counts, and they cover the whole unit, private land included. Source: CPW harvest reports, 2022–2024.

Herd numbers cover the whole North Grand Mesa herd unit (D-12), which also takes in Units 41 and 42: CPW manages herds, not units. Source: CPW post-hunt population estimate, 2025.

Neighbors

Units 42, 52, 41, 411 and 521, nearest first.

From each unit's own page; dates there.

What this page can't tell you

Closures, private ground, this year's pressure and animal locations.
  • Closures. Forest, fire and road closure orders change through the season and aren't checked here. The managing agency's current order governs.
  • Private ground. Land with no public hunting access is hunted only with the owner's permission, and the public-land share above leaves it out.
  • This year's pressure. CPW's hunter numbers run a year or more behind the season you're planning.
  • Animal locations. These are terrain, access, harvest and herd figures, and CPW's mapped ranges are range lines; none of them places an animal.

Sources

23 datasets and studies, dated where the source dates them.
  1. Deer statistics: population estimates and harvest reports — Colorado Parks and Wildlife
  2. Colorado big game hunting: brochure, seasons and hunt codes — Colorado Parks and Wildlife
  3. Game Management Unit boundaries (Hunting Atlas) — Colorado Parks and Wildlife On the map: unit boundaries, 2025.
  4. COMaP: Colorado Ownership, Management and Protection — Colorado Natural Heritage Program, 2026-10-12 On the map: public land by manager, mapped 2026-07-29.
  5. 3D Elevation Program (3DEP), 1/3 arc-second — U.S. Geological Survey On the map: shaded relief from 5 m and 10 m lidar elevation, mapped 2026-10-04; elevation bands and slope, mapped 2026-10-04.
  6. LANDFIRE Existing Vegetation Type (LF 2024) — U.S. Geological Survey / USDA Forest Service, LF2024
  7. 3DEP lidar point clouds (canopy height model) — U.S. Geological Survey
  8. COTREX: Colorado Trail Explorer — Colorado Parks and Wildlife On the map: trailheads, 2024.
  9. Motor Vehicle Use Maps (MVUM) — USDA Forest Service On the map: roads by vehicle class, drawn as open on the selected season's opener, mapped 2026-08-22.
  10. Highways and major roads — Colorado Department of Transportation On the map: highways, mapped 2026-07-31.
  11. SNOTEL network: daily snow depth and snow water equivalent — USDA Natural Resources Conservation Service, 2026-10-20 On the map: SNOTEL stations.
  12. U.S. Drought Monitor — National Drought Mitigation Center, 2026-10-13
  13. MOD13Q1 vegetation indices (NDVI), 250 m 16-day — NASA LP DAAC, 2026-09-29
  14. National Weather Service 7-day gridpoint forecast — National Weather Service, 2026-10-21
  15. National Weather Service Area Forecast Discussion (BOU, GJT, PUB) — National Weather Service, 2026-10-21
  16. Influence of well pad activity on winter habitat selection patterns of mule deer — Sawyer, Kauffman and Nielson, Journal of Wildlife Management 73(7), 2009
  17. Sex-specific behaviors of hunted mule deer during rifle season — Rodgers, Sawyer, Mong, Stephens and Kauffman, Journal of Wildlife Management 85(2), 2021
  18. Ungulate migrations of the western United States, volume 4 — Kauffman, Lowrey, Beaupre and others, USGS Scientific Investigations Report 2024-5006, 2024
  19. Mule deer (Odocoileus hemionus) fact sheet — USDA Natural Resources Conservation Service, Colorado, Fact sheet, March 2000, 2000
  20. Timing of seasonal migration in mule deer: effects of climate, plant phenology, and life-history characteristics — Monteith, Bleich, Stephenson, Pierce, Conner, Klaver and Bowyer, Ecosphere 2(4), 2011
  21. Wildland Fire Interagency Geospatial Services (WFIGS) fire perimeters — National Interagency Fire Center On the map: burns over 100 acres since 2020, mapped 2026-06-29.
  22. Gazetteer files, places — U.S. Census Bureau, 2024 On the map: towns, 2024.
  23. Species Activity Mapping: mule deer seasonal ranges — Colorado Parks and Wildlife, 2025 On the map: CPW mapped ranges, 2025.

Build a plan for Unit 421, free.

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POIs are terrain candidates — places worth checking, not animal locations.