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Colorado GMU 231 mule deer: terrain, access and seasons

Unit 231'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 23% for 21 hunters.

Size
178 sq mi
CPW unit boundary, 2025
Counties
Routt, Rio Blanco, Garfield
Elevation
6,910–12,130 ft
USGS 3DEP, 2026-10-19
Huntable public land
64%
COMaP, 2026-10-12
Second rifle license, 2026
Draw buck
CPW 2026 big game brochure. Colorado has no OTC mule deer license
Success
23%
CPW harvest survey, 2024
Hunters
21
CPW harvest survey, 2024
Hunter-days per sq mi
0.7
CPW, 2024
Road miles, any vehicle
75 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
0 in
Deepest at Crosho SNOTEL, 2026-10-20

In short

A mid-elevation, mostly timbered draw-only unit. Most of Unit 231 sits between 8,000 and 10,000 feet, with more conifer than anything else and aspen next, then shrubland; about a tenth of it rises above 11,000 feet. Just under 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 143 hunters across all seasons in 2024, down from 160 in 2022. Every license here is drawn, as for all Colorado mule deer.

Licenses and draw

Second rifle in Unit 231, 2026: a draw buck license (D-M-131-O2-R).

  • D-M-131-O2-R buck, draw 2026 draw: drawn on choice 2 for residents and nonresidents

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 231 sits among its neighbors.

131 26 15 13 12 231

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

Conditions

As of Oct 21: no snow on the ground at the 3 SNOTEL stations near the unit; exceptional drought (D4) on the US Drought Monitor over 33.9% of the unit.

Rebuilt nightly; sources at the end of the page.

Item Value Data
Snow (SNOTEL) Crosho (8,960 ft): 0 in deep, SWE 0 inBear River (9,100 ft, 0.1 mi out): 0 in deep, SWE 0.3 inTrapper Lake (9,750 ft, 3.3 mi out): 0 in deep, SWE 0.1 in 2026-10-20 2026-10-20
Drought D4, Exceptional droughtShare of the unit: D0 or worse 100% · D1 or worse 100% · D2 or worse 100% · D3 or worse 100% · D4 33.9% USDM 2026-10-13 USDM 2026-10-13
Greenness vs normal, Sep 14–29 96% 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 150,148, 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 55° 36°55° 40°53° 34°49° 30°47° 30°50° 29°48° 29°
Precip 0.1 in0.2 in0 in0.1 in0 in0 in0 in
Snow 0 in0 in0 in0 in0 in0 in0 in
Gusts 21 mph25 mph32 mph12 mph12 mph12 mph15 mph
10,000–11,000 ft NWS GJT gridpoint 151,147, 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 52° 37°52° 39°50° 33°46° 29°44° 29°46° 28°45° 27°
Precip 0.1 in0.2 in0 in0.1 in0 in0 in0 in
Snow 0 in0 in0 in0 in0 in0 in0 in
Gusts 23 mph28 mph32 mph13 mph13 mph12 mph15 mph

Access

Unit 231 has 8 trailheads and about 75 miles of road any vehicle may drive on the second rifle opener, plus 12 more that need high clearance. About a third 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
8
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
75 mi
High clearance
12 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
34.5%
30–60 min
31.3%
60–90 min
23%
Over 90 min
11.2%

Hunt codes and draw results

1 hunt code 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-131-O2-R buck 2024 35 29 17 0 points 20 7 0 points
2025 35 48 23 0 points 17 4 0 points
2026 70 26 41 Choice 2 10 12 Choice 2

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 231.

  • Across Utah and Nevada, GPS-collared mule deer avoided high-severity burns at fine scale for up to 30 years after a fire.

    Mills et al., 2026 Single study

  • 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

Build a plan for Unit 231, free.

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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

6,910–12,130 ft; conifer 36.3% and aspen 25.8%; burns: Crosho Fire (2025).

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

Elevation Acres per 1,000 ft band. USGS 3DEP.
  1. 7k–8k ft 18,770 ac
  2. 8k–9k ft 40,510 ac
  3. 9k–10k ft 26,100 ac
  4. 10k–11k ft 19,480 ac
  5. 11k–12k ft 8,580 ac
  6. 12k–13k ft 52 ac
Table view
BandAcres
7,000–8,000 ft18,770 ac
8,000–9,000 ft40,510 ac
9,000–10,000 ft26,100 ac
10,000–11,000 ft19,480 ac
11,000–12,000 ft8,580 ac
12,000–13,000 ft52 ac
Slope Share of the unit per slope class.
  1. Under 5° 23.7%
  2. 5–15° 49.3%
  3. 15–25° 20.3%
  4. 25–35° 5.3%
  5. 35°+ 1.4%
Table view
Slope classShare
Flat (under 5°)23.7%
Gentle (5–15°)49.3%
Moderate (15–25°)20.3%
Steep (25–35°)5.3%
Very steep (35° and up)1.4%
Aspect Share of non-flat ground facing each way.
  1. N 16.3%
  2. NE 17.3%
  3. E 16.5%
  4. SE 13.5%
  5. S 7.7%
  6. SW 7.5%
  7. W 8.6%
  8. NW 12.6%
Table view
AspectShare
North16.3%
Northeast17.3%
East16.5%
Southeast13.5%
South7.7%
Southwest7.5%
West8.6%
Northwest12.6%
Vegetation LF2024 existing vegetation, groups of 1% or more.
  1. Conifer 36.3%
  2. Aspen 25.8%
  3. Shrubland 18.2%
  4. Grass & meadow 6.8%
  5. Riparian & wetland 5%
  6. Farmland 2.9%
  7. Rock & scree 2%
  8. Developed 1.1%
Table view
Vegetation groupShare
Conifer36.3%
Aspen25.8%
Shrubland18.2%
Grass & meadow6.8%
Riparian & wetland5%
Farmland2.9%
Rock & scree2%
Developed1.1%
Item Value Data
Burned 0–3 years ago 2,100 acCrosho Fire (2025), 2,100 ac NIFC since 2020 NIFC since 2020
Openings in timber 503 openings of 1–40 ac, from lidar covering 49.8% of the unit 2026-10-19 2026-10-19
Habitat Score, second rifle Share of 72,100 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%
0.5–10.7%
1–1.510%
1.5–239.6%
2–2.538.3%
2.5–310.2%
3–3.51.3%
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 White River herd (D-7) estimate for 2025 and hunter density, 2024.

CPW counted 21 second rifle hunters in 2024; on so few, the success rate swings widely from year to year. Across all seasons, hunters fell by about a tenth between 2022 and 2024. Unit 231 is one of 9 units in CPW's White River mule deer herd (DAU D-7), estimated at about 31,000 mule deer after the 2025 hunt, with 33 bucks per 100 does.

Hunters, harvest and success
Season Year Hunters Harvest Success
Second rifle 2022 63 14 23%
2023 25 5 22%
2024 21 5 23%
All seasons 2022 160 35 22%
2023 124 22 18%
2024 143 22 15%

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

Item Value Data
Hunter density 5 hunter-days per sq mi, all seasons CPW 2024 CPW 2024
Herd estimate (White River, D-7) 31,170 post-hunt · 36,460 in 2019 CPW 2025 CPW 2025
Buck:doe ratio 33 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 White River herd unit (D-7), which also takes in Units 11, 12, 13, 22, 23, 24, 131 and 211: CPW manages herds, not units. Source: CPW post-hunt population estimate, 2025.

Neighbors

Units 131, 26, 15, 13 and 12, 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

24 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. 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.
  8. 3DEP lidar point clouds (canopy height model) — U.S. Geological Survey
  9. COTREX: Colorado Trail Explorer — Colorado Parks and Wildlife On the map: trailheads, 2024.
  10. 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.
  11. Highways and major roads — Colorado Department of Transportation On the map: highways, mapped 2026-07-31.
  12. SNOTEL network: daily snow depth and snow water equivalent — USDA Natural Resources Conservation Service, 2026-10-20 On the map: SNOTEL stations.
  13. U.S. Drought Monitor — National Drought Mitigation Center, 2026-10-13
  14. MOD13Q1 vegetation indices (NDVI), 250 m 16-day — NASA LP DAAC, 2026-09-29
  15. National Weather Service 7-day gridpoint forecast — National Weather Service, 2026-10-21
  16. National Weather Service Area Forecast Discussion (BOU, GJT, PUB) — National Weather Service, 2026-10-21
  17. Influence of well pad activity on winter habitat selection patterns of mule deer — Sawyer, Kauffman and Nielson, Journal of Wildlife Management 73(7), 2009
  18. Long-term benefits of burns for large mammal habitat undermined by large, severe fires in the American West — Mills, Leclerc, Ditmer, Steel, Stoner, Sexton and others, Ecography 2026 (read via the Northern Rockies Fire Science Network summary), 2026
  19. Sex-specific behaviors of hunted mule deer during rifle season — Rodgers, Sawyer, Mong, Stephens and Kauffman, Journal of Wildlife Management 85(2), 2021
  20. Ungulate migrations of the western United States, volume 4 — Kauffman, Lowrey, Beaupre and others, USGS Scientific Investigations Report 2024-5006, 2024
  21. Mule deer (Odocoileus hemionus) fact sheet — USDA Natural Resources Conservation Service, Colorado, Fact sheet, March 2000, 2000
  22. 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
  23. Gazetteer files, places — U.S. Census Bureau, 2024 On the map: towns, 2024.
  24. Species Activity Mapping: mule deer seasonal ranges — Colorado Parks and Wildlife, 2025 On the map: CPW mapped ranges, 2025.

Build a plan for Unit 231, free.

Start free

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