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Colorado GMU 51 elk: terrain, access and seasons

Unit 51'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 17% for 96 hunters.

Size
503 sq mi
CPW unit boundary, 2025
County
Douglas
Elevation
5,360–9,830 ft
USGS 3DEP, 2026-10-19
Huntable public land
46%
COMaP, 2026-10-12
Second rifle license, 2026
Draw bull, cow
CPW 2026 big game brochure
Success
17%
CPW harvest survey, 2024
Hunters
96
CPW harvest survey, 2024
Hunter-days per sq mi
1
CPW, 2024
Road miles, any vehicle
730 mi
MVUM + CDOT, open on the Oct 24 opener
Median Habitat Score
1.9 of 5
Ranks 68th of 128 for second rifle. Glassline, v20, 2026-10-19

In short

A low-elevation, half-open draw-only unit with more hunters than in 2022. Most of Unit 51 sits between 6,000 and 8,000 feet, with more conifer than anything else and grass and meadow next, then shrubland. Just under half of the unit is huntable public land, and about a fifth of that ground is more than an hour and a half on foot from a drivable road. CPW's survey counted 623 hunters across all seasons in 2024, up from 524 in 2022, while second rifle success rose from 8% to 17%. Every license here is drawn.

Licenses and draw

Second rifle in Unit 51, 2026: a draw bull license (E-M-051-O2-R) and a draw cow license (E-F-051-O2-R).

  • E-M-051-O2-R bull, draw 2026 draw: drawn out at 0 points for residents and nonresidents
  • E-F-051-O2-R cow, draw 2026 draw: residents drawn on choice 2; 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 51 sits among its neighbors.

461 511 501 391 51

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

Conditions

As of Oct 21: no SNOTEL station sits within 6 mi of the unit; extreme drought (D3) on the US Drought Monitor over 65.7% of the unit.

Rebuilt nightly; sources at the end of the page.

Item Value Data
SNOTEL No SNOTEL station within 6 mi of the unit
Drought D3, Extreme droughtShare of the unit: D0 or worse 100% · D1 or worse 100% · D2 or worse 100% · D3 or worse 65.7% USDM 2026-10-13 USDM 2026-10-13
Greenness vs normal, Sep 14–29 108% 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, issued Oct 21; the second rifle opener, Oct 24, is marked, and the front is shaded.

8,000–9,000 ft NWS BOU gridpoint 60,42, issued 2026-10-21. Gusts and lows: gridpoint only. Front Sat 10/24: BOU: 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° 46°67° 55°68° 55°54° 43°49° 41°49° 40°54° 40°
Precip 0 in0 in0 in0.1 in0.1 in0 in0 in
Snow 0 in0 in0 in0 in0 in0 in0 in
Gusts 16 mph21 mph33 mph25 mph17 mph15 mph16 mph

Access

Unit 51 has 48 trailheads and about 730 miles of road any vehicle may drive on the second rifle opener, plus 96 more that need high clearance. Just over two-fifths of the huntable public ground is within a 30-minute walk of a drivable road, and about a fifth is more than an hour and a half away.

Trailheads
48
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
730 mi
High clearance
96 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
43.8%
30–60 min
23.6%
60–90 min
14.3%
Over 90 min
18.2%

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
E-M-051-O2-R bull 2024 50 72 32 1 point 8 3 1 point
2025 50 51 29 0 points 6 5 0 points
2026 50 51 32 0 points 4 3 0 points
E-F-051-O2-R cow 2024 50 21 39 Choice 2 3 4 Choice 2
2025 50 23 40 Choice 2 0 0 None Drawn
2026 50 17 39 Choice 2 0 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 elk have behaved where they were studied, not where they are in Unit 51.

  • 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 51, 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

5,360–9,830 ft; conifer 43% and grass & meadow 19.3%; burns: Turkey Tracks Fire (2025).

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

Elevation Acres per 1,000 ft band. USGS 3DEP.
  1. 5k–6k ft 49,080 ac
  2. 6k–7k ft 119,770 ac
  3. 7k–8k ft 87,710 ac
  4. 8k–9k ft 59,980 ac
  5. 9k–10k ft 3,540 ac
Table view
BandAcres
5,000–6,000 ft49,080 ac
6,000–7,000 ft119,770 ac
7,000–8,000 ft87,710 ac
8,000–9,000 ft59,980 ac
9,000–10,000 ft3,540 ac
Slope Share of the unit per slope class.
  1. Under 5° 24.3%
  2. 5–15° 39.2%
  3. 15–25° 23.4%
  4. 25–35° 11.2%
  5. 35°+ 2%
Table view
Slope classShare
Flat (under 5°)24.3%
Gentle (5–15°)39.2%
Moderate (15–25°)23.4%
Steep (25–35°)11.2%
Very steep (35° and up)2%
Aspect Share of non-flat ground facing each way.
  1. N 12.3%
  2. NE 14.1%
  3. E 14%
  4. SE 10.5%
  5. S 9.2%
  6. SW 11.8%
  7. W 14.5%
  8. NW 13.6%
Table view
AspectShare
North12.3%
Northeast14.1%
East14%
Southeast10.5%
South9.2%
Southwest11.8%
West14.5%
Northwest13.6%
Vegetation LF2024 existing vegetation, groups of 1% or more.
  1. Conifer 43%
  2. Grass & meadow 19.3%
  3. Shrubland 17.1%
  4. Developed 13.9%
  5. Riparian & wetland 3.5%
  6. Pinyon-juniper 2.3%
Table view
Vegetation groupShare
Conifer43%
Grass & meadow19.3%
Shrubland17.1%
Developed13.9%
Riparian & wetland3.5%
Pinyon-juniper2.3%
Item Value Data
Burned 0–3 years ago 200 acTurkey Tracks Fire (2025), 200 ac NIFC since 2020 NIFC since 2020
Openings in timber 1,476 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 146,200 ac of huntable public ground in each score band. Median 1.9. Scoring v20, computed 2026-10-19.
Table view
ScoreShare of scored ground
0–0.52.7%
0.5–112.3%
1–1.518.9%
1.5–223.2%
2–2.519.8%
2.5–315.1%
3–3.58%
3.5–40.2%
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 Castle Rock herd (E-51) estimate for 2025 and hunter density, 2024.

Second rifle success rose from 8% to 17% between 2022 and 2024, while the season's hunters rose by just under a fifth. Across all seasons, hunters rose by about a fifth between 2022 and 2024. Unit 51 is one of 6 units in CPW's Castle Rock herd unit (E-51), estimated at about 3,500 elk after the 2025 hunt, with 40 bulls per 100 cows.

Hunters, harvest and success
Season Year Hunters Harvest Success
Second rifle 2022 82 7 8%
2023 77 26 34%
2024 96 16 17%
All seasons 2022 524 176 34%
2023 578 163 28%
2024 623 188 30%

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

Item Value Data
Hunter density 10 hunter-days per sq mi, all seasons CPW 2024 CPW 2024
Herd estimate (Castle Rock, E-51) 3,480 post-hunt · 1,930 in 2019 CPW 2025 CPW 2025
Bull:cow ratio 40 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 Castle Rock herd unit (E-51), which also takes in Units 104, 105, 106, 110 and 111: CPW manages herds, not units. Source: CPW post-hunt population estimate, 2025.

Neighbors

Units 461, 511, 501, 391 and 512, 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

24 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. 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. 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. Wildfire extends the shelf life of elk nutritional resources regardless of fire severity — Snobl, Proffitt and Millspaugh, Ecosphere 13(7), 2022
  19. Behavioral responses of male elk to hunting risk — Smith, Spitz, Brown, Wisdom, Rowland, Forrester, Johnson and Clark, Journal of Wildlife Management 86, 2022
  20. 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
  21. 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
  22. SNOTEL network: daily snow depth and snow water equivalent — USDA Natural Resources Conservation Service On the map: SNOTEL stations.
  23. Gazetteer files, places — U.S. Census Bureau, 2024 On the map: towns, 2024.
  24. Species Activity Mapping: elk seasonal ranges — Colorado Parks and Wildlife, 2025 On the map: CPW mapped ranges, 2025.

Build a plan for Unit 51, free.

Start free

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