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Colorado GMU 851 elk: terrain, access and seasons

Unit 851's terrain, access, seasons and CPW elk 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 27% for 87 hunters.

Size
438 sq mi
CPW unit boundary, 2025
Counties
Costilla, Las Animas
Elevation
5,990–14,040 ft
USGS 3DEP, 2026-10-19
Huntable public land
13%
COMaP, 2026-10-12
Second rifle license, 2026
OTC bull · Draw bull, cow
CPW 2026 big game brochure
Success
27%
CPW harvest survey, 2024
Hunters
87
CPW harvest survey, 2024
Hunter-days per sq mi
1.1
CPW, 2024
Road miles, any vehicle
59 mi
MVUM + CDOT, open on the Oct 24 opener
Median Habitat Score
2.7 of 5
Ranks 22nd of 128 for second rifle. Glassline, v20, 2026-10-19
Snow now
1 in
Deepest at Whiskey Ck SNOTEL, 2026-10-20

In short

A mid-elevation, mostly timbered OTC unit with more far-from-road ground than most units. Most of Unit 851 sits between 7,000 and 9,000 feet, mostly conifer with pinyon-juniper after it. Just over a tenth of the unit is huntable public land, just over two-thirds of it over 90 minutes' walk from a road. CPW's survey counted 579 hunters across all seasons in 2024, while second rifle success rose from 23% to 27%. Archery sells over-the-counter either-sex and cow licenses to residents only; second and third rifle sell over-the-counter bull licenses; the other seasons are draw only.

Licenses and draw

Second rifle in Unit 851, 2026: an over-the-counter bull license (E-M-000-U2-R), a draw bull license (E-M-851-O2-R) and a draw cow license (E-F-085-O2-R).

  • E-M-000-U2-R bull, over the counter
  • E-M-851-O2-R bull, draw 2026 draw: residents drawn out at 14 points; nonresidents none drawn
  • E-F-085-O2-R cow, draw 2026 draw: drawn out at 0 points 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 851 sits among its neighbors.

85 83 140 134 141 851

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

Conditions

As of Oct 21: 1 in of snow at Whiskey Ck SNOTEL, the deepest reading near the unit; extreme drought (D3) on the US Drought Monitor over 24.7% of the unit.

Rebuilt nightly; sources at the end of the page.

Item Value Data
Snow (SNOTEL) Whiskey Ck (10,260 ft): 1 in deep, SWE 0 inCulebra #2 (10,560 ft, 1.8 mi out): 0 in deep, SWE 0 inApishapa (10,000 ft, 6 mi out): 1 in deep, SWE 0 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 24.7% USDM 2026-10-13 USDM 2026-10-13
Greenness vs normal, Sep 14–29 111% 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, and the front is shaded.

8,000–9,000 ft NWS PUB gridpoint 82,12, issued 2026-10-21. Gusts and lows: gridpoint only. Front Sat 10/24: PUB: cold front Saturday (discussion of 10/21).
Wed 10/21 Thu 10/22 Fri 10/23 Sat 10/24 Front Opener Sun 10/25 Mon 10/26 Tue 10/27
High / low 67° 37°68° 52°65° 47°55° 44°51° 41°53° 40°58° 38°
Precip 0 in0 in0 in0.5 in0.6 in0 in0 in
Snow 0 in0 in0 in0 in0 in0 in0 in
Gusts 14 mph26 mph33 mph21 mph10 mph14 mph14 mph
10,000–11,000 ft NWS PUB gridpoint 74,14, issued 2026-10-21. Gusts and lows: gridpoint only. Front Sat 10/24: PUB: cold front Saturday (discussion of 10/21).
Wed 10/21 Thu 10/22 Fri 10/23 Sat 10/24 Front Opener Sun 10/25 Mon 10/26 Tue 10/27
High / low 62° 37°62° 46°58° 42°48° 39°45° 37°46° 35°49° 35°
Precip 0 in0.1 in0 in0.4 in0.4 in0 in0 in
Snow 0 in0 in0 in0 in0 in0 in0 in
Gusts 10 mph17 mph39 mph15 mph10 mph9 mph12 mph

Access

Unit 851 has 7 trailheads and about 59 miles of road any vehicle may drive on the second rifle opener, plus 7 more that need high clearance. About a tenth of the huntable public ground is within a 30-minute walk of a drivable road, and just over two-thirds is more than an hour and a half away.

Trailheads
7
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
59 mi
High clearance
7 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
12.4%
30–60 min
7.5%
60–90 min
9.7%
Over 90 min
70.4%

Hunt codes and draw results

3 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
E-M-000-U2-R bull Over the counter: no draw
E-M-851-O2-R bull 2024 5 30 4 15 points 12 1 19 points
2025 5 22 4 15 points 4 1 29 points
2026 5 26 5 14 points 7 0 None Drawn
E-F-085-O2-R cow 2024 50 55 36 0 points 13 10 0 points
2025 50 69 35 0 points 20 9 0 points
2026 50 73 33 0 points 22 9 0 points

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 elk have behaved where they were studied, not where they are in Unit 851.

  • In Montana GPS work, rifle-season elk tended to hold about a mile or more from open motorized routes, in blocks of 5,000 acres or more.

    Ranglack et al., 2017 Established finding

  • At Oregon's Starkey Experimental Forest, bulls chose more canopy and kept away from open roads by day during hunts, and the shift was stronger in rifle seasons than in archery.

    Smith et al., 2022 Single study

  • In Montana, collared elk shifted onto ground closed to public hunting once rifle seasons opened, ahead of security cover on public land.

    Proffitt et al., 2013 Established finding

Read next: Colorado second rifle elk, 2026 · How to e-scout a Colorado elk unit

Build a plan for Unit 851, free.

Start free

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

5,990–14,040 ft; conifer 65.1% and pinyon-juniper 10.6%; no mapped burns since 2020.

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

Elevation Acres per 1,000 ft band. USGS 3DEP.
  1. 6k–7k ft 43,800 ac
  2. 7k–8k ft 105,480 ac
  3. 8k–9k ft 53,170 ac
  4. 9k–10k ft 36,330 ac
  5. 10k–11k ft 20,470 ac
  6. 11k–12k ft 12,860 ac
  7. 12k–13k ft 5,820 ac
  8. 13k–14k ft 950 ac
Table view
BandAcres
6,000–7,000 ft43,800 ac
7,000–8,000 ft105,480 ac
8,000–9,000 ft53,170 ac
9,000–10,000 ft36,330 ac
10,000–11,000 ft20,470 ac
11,000–12,000 ft12,860 ac
12,000–13,000 ft5,820 ac
13,000–14,000 ft950 ac
Slope Share of the unit per slope class.
  1. Under 5° 9.9%
  2. 5–15° 35.4%
  3. 15–25° 36.3%
  4. 25–35° 16.5%
  5. 35°+ 1.9%
Table view
Slope classShare
Flat (under 5°)9.9%
Gentle (5–15°)35.4%
Moderate (15–25°)36.3%
Steep (25–35°)16.5%
Very steep (35° and up)1.9%
Aspect Share of non-flat ground facing each way.
  1. N 14.2%
  2. NE 15.9%
  3. E 15.8%
  4. SE 14.1%
  5. S 12%
  6. SW 9.3%
  7. W 8.3%
  8. NW 10.5%
Table view
AspectShare
North14.2%
Northeast15.9%
East15.8%
Southeast14.1%
South12%
Southwest9.3%
West8.3%
Northwest10.5%
Vegetation LF2024 existing vegetation, groups of 1% or more.
  1. Conifer 65.1%
  2. Pinyon-juniper 10.6%
  3. Grass & meadow 7.9%
  4. Shrubland 7.8%
  5. Riparian & wetland 2.4%
  6. Rock & scree 1.9%
  7. Aspen 1.9%
Table view
Vegetation groupShare
Conifer65.1%
Pinyon-juniper10.6%
Grass & meadow7.9%
Shrubland7.8%
Riparian & wetland2.4%
Rock & scree1.9%
Aspen1.9%
Item Value Data
Burns No burned acres in the unit since 2020 NIFC NIFC
Openings in timber 2,468 openings of 1–40 ac, from lidar covering 99.9% of the unit 2026-10-19 2026-10-19
Habitat Score, second rifle Share of 36,300 ac of huntable public ground in each score band. Median 2.7. Scoring v20, computed 2026-10-19.
Table view
ScoreShare of scored ground
0–0.52.2%
0.5–112.6%
1–1.55.4%
1.5–26.6%
2–2.512.6%
2.5–336.5%
3–3.523.4%
3.5–40.6%
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 Trinchera herd (E-33) estimate for 2025 and hunter density, 2024.

Second rifle success rose from 23% to 27% between 2022 and 2024, while the season's hunters fell by about a fifth. Across all seasons, hunters held about steady between 2022 and 2024. Unit 851 is one of 4 units in CPW's Trinchera herd unit (E-33), estimated at about 14,000 elk after the 2025 hunt, with 26 bulls per 100 cows.

Hunters, harvest and success
Season Year Hunters Harvest Success
Second rifle 2022 112 26 23%
2023 80 15 18%
2024 87 24 27%
All seasons 2022 614 149 24%
2023 545 186 34%
2024 579 175 30%

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

Item Value Data
Hunter density 7 hunter-days per sq mi, all seasons CPW 2024 CPW 2024
Herd estimate (Trinchera, E-33) 14,470 post-hunt · 16,480 in 2019 CPW 2025 CPW 2025
Bull:cow ratio 26 bulls per 100 cows 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 Trinchera herd unit (E-33), which also takes in Units 83, 85 and 140: CPW manages herds, not units. Source: CPW post-hunt population estimate, 2025.

Neighbors

Units 85, 83, 140, 134 and 141, 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. Finding elk is still your job.

Sources

23 datasets and studies, dated where the source dates them.
  1. Elk 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. Effects of bull age on conception dates and pregnancy rates of cow elk — Noyes, Johnson, Bryant, Findholt and Thomas, Journal of Wildlife Management 60(3), 1996
  17. Security areas for elk during archery and rifle hunting seasons — Ranglack, Proffitt, Canfield, Gude, Rotella and Garrott, Journal of Wildlife Management 81(5), 2017
  18. Behavioral responses of male elk to hunting risk — Smith, Spitz, Brown, Wisdom, Rowland, Forrester, Johnson and Clark, Journal of Wildlife Management 86, 2022
  19. Effects of hunter access and habitat security on elk habitat selection in landscapes with a public and private land matrix — Proffitt, Gude, Hamlin and Messer, Journal of Wildlife Management 77(3), 2013
  20. Plasticity in elk migration timing is a response to changing environmental conditions — Rickbeil, Merkle, Anderson, Atwood, Beckmann, Cole, Courtemanch, Dewey, Gustine, Kauffman, McWhirter, Mong, Proffitt, White and Middleton, Global Change Biology 25, 2019
  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: elk seasonal ranges — Colorado Parks and Wildlife, 2025 On the map: CPW mapped ranges, 2025.

Build a plan for Unit 851, free.

Start free

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