Unit S21 (Cow Creek/Wetterhorn Peak)
Colorado Hunting Guide — Bighorn Sheep
Unit S21 lies in Ouray, Gunnison, San Miguel and Hinsdale counties. CPW bounds it by Colo. 62 and U.S. 550 among others. CPW's harvest estimates put bighorn sheep success here as high as 71%. Federal land covers about 87% of it. Check land status on a current map before you plan a route.
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Bighorn Sheep Hunting in Unit S21
Unit S21 lies in Ouray, Gunnison, San Miguel and Hinsdale counties. CPW bounds it by Colo. 62 and U.S. 550 among others. CPW's harvest estimates put bighorn sheep success here as high as 71%. Federal land covers about 87% of it. Check land status on a current map before you plan a route.
Where to Find Bighorn Sheep in Unit S21
What CPW publishes for unit S21 is a boundary, not a bighorn sheep map. Every place named below sits inside the unit line. Which of them holds animals in your season is for you to find out. The unit lies in Ouray, Gunnison, San Miguel and Hinsdale counties.
The lines of the unit: Colo. 62, U.S. 550 and Ouray-Montrose
CPW has unit S21 bounded on the north by Colo. 62, U.S. 550, Ouray-Montrose and Ouray-Gunnison Co. lines, to Uncompahgre National Forest line, and there to Big Blue Creek; on the east and south by Big Blue Creek to Uncompahgre Peak, Uncompahgre-Animas River divide, Ouray-Hinsdale Co. line, Engineer Mountain, Uncompahgre-Lake Fork-Animas River divide, San Miguel-San Juan and San Miguel-Dolores Co. lines and Lizard Head Pass; on the west by Colo. 145 and U.S. 62. That is a legal description, not a habitat map. What it does give you is the way in: the rivers and highways you cross, and the divides that decide which drainage you end up in.
High ground inside the line: Mount Sneffels, Vermilion Peak and Potosi Peak
Named high points inside the unit include Mount Sneffels at 14,106 feet, Vermilion Peak at 13,868 feet, Potosi Peak at 13,774 feet, Ulysses S Grant Peak at 13,735 feet and Teakettle Mountain at 13,713 feet. Several carry a public-land flag in our data, which makes them the first places to try for a view. Sheep need rock to escape into and will not stand far from it.
Holding ground: Lena Basin, Alaska Basin and Bridal Veil Basin
Below them sit Lena Basin at 12,519 feet, Alaska Basin at 12,445 feet, Bridal Veil Basin at 12,377 feet, Mud Lake Basin at 12,261 feet and La Junta Basin at 12,227 feet. Those are the basins, parks and bottoms this unit has, and they are what you glass into from above. Two you can watch from a single knob is worth more than five you have to drive between.
Public ground to start from: Billy Creek SWA, Billy Creek SWA - Beckett Tract and Billy Creek SWA - Billy Creek Tract
CPW lists Billy Creek SWA, Billy Creek SWA - Beckett Tract, Billy Creek SWA - Billy Creek Tract, Billy Creek SWA - Carmichael Tract and Billy Creek SWA - Chaffee Gulch inside this unit as ground open to public hunting. Each property sets its own restrictions, and the agency's page for it is where they are written down. Federal land covers about 87% of the unit on top of those.
Water: Hout Spring, Mud Spring and Homer Brown Spring
Named sources include Hout Spring, Mud Spring, Homer Brown Spring, Groff Spring, Sheep Spring and Bear Creek Falls. Nothing in the data says which of them run in autumn, so a scouting trip earns its fuel.
The herd this unit belongs to: RBS-21
CPW does not manage bighorn sheep unit by unit. It manages them as data analysis unit RBS-21, and unit S21 is one piece of it. The rest of RBS-21 is unit S33. So the objective behind your tag was written for that whole area, and a neighbouring unit in the same herd is a fairer comparison than the statewide figure.
Unit S21 terrain and land status
Measured from the unit boundary, not from the agency write-up
Named features inside the unit
Glass from: Mount Sneffels (14,106 ft), Vermilion Peak (13,868 ft), Potosi Peak (13,774 ft), Ulysses S Grant Peak (13,735 ft)
Holding ground: Richmond Pass (12,664 ft), East Basin (12,648 ft), Lena Basin (12,519 ft), Billy Creek SWA, Billy Creek SWA - Beckett Tract
Every one of these was tested against the unit polygon before it went on the map. They are starting points, not agency recommendations.
How to Hunt Bighorn Sheep in Unit S21
Bighorn Sheep Success Rates
CPW's 2023 harvest estimates put bighorn sheep success in unit S21 at 71% — 10 animals taken by 14 hunters. On a sample that small the percentage moves several points with one animal, so read the hunter count beside it.
These are the agency's own printed figures for this unit, not a modelled estimate and not a state average. They describe one season, so check CPW's current harvest estimates before you read a trend into them.
Bighorn Sheep Draw Odds
| Season | Tags | Applicants | Draw % | Pts Req |
|---|---|---|---|---|
| Rifle — 1st Season ewe only (resident) | 3 | 33 | 9.1% | 3 |
| Rifle — 1st Season ewe only (nonresident) | 1 | 20 | 5.0% | 3 |
| Rifle — 1st Season ewe only (resident) | 2 | 21 | 9.5% | 2 |
| Rifle — 1st Season ewe only (nonresident) | 0 | 0 | 0.0% | — |
| Rifle — 1st Season ram only (resident) | 6 | 650 | 0.9% | 3 |
| Rifle — 1st Season ram only (nonresident) | 1 | 874 | 0.1% | 3 |
Data from 2026 draw results. Each row is one residency pool — read the label before the number.
Open in Draw Odds EngineCPW's 2026 draw recap for bighorn sheep in unit S21, by hunt code, with resident and nonresident kept apart because the two draw from different licence pools:
- SMS21O1R — Rifle, 1st Season, Ram Only, nonresident: 874 applicants for 1 licences, 0.1% drawn, 3 preference points needed
- SMS21O1R — Rifle, 1st Season, Ram Only, resident: 650 applicants for 6 licences, 0.9% drawn, 3 preference points needed
- SFS21O1R — Rifle, 1st Season, Ewe Only, resident: 33 applicants for 3 licences, 9.1% drawn, 3 preference points needed
- SFS21S1R — Rifle, 1st Season, Ewe Only, resident: 21 applicants for 2 licences, 9.5% drawn, 2 preference points needed
Colorado runs a pure preference-point draw, so the point figure above is the requirement the agency published for that code in that year, not a forecast for the next one. There are 1 further code-and-residency combinations in the recap for this unit. Figures checked against CPW's own statistics pages on 2026-06-09.
Unit Logistics & Expectations
Frequently Asked Questions
Where is Colorado unit S21?
What is the bighorn sheep success rate in unit S21?
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Every fact on this page is tied to a primary source below. Last fact-checked 2026-10-23.
- Colorado Sheep & Goat Hunting Brochure — Game Management Unit (GMU) Descriptions (pp. 16-17) — Colorado Parks and Wildlife · supports: GMU boundary description, Counties the unit lies in, Data analysis unit (DAU) the unit belongs to · accessed 2026-10-22
- 2023 Colorado Rocky Mountain bighorn sheep Harvest Estimates — Colorado Parks and Wildlife · supports: Percent success for bighorn sheep in unit S21, Hunters and harvest by weapon and season · accessed 2026-10-22
- CPW CPWAdminData feature service — GMU and sheep/goat unit boundaries — Colorado Parks and Wildlife GIS Unit · supports: Mapped extent of the unit, Which named ground falls inside the unit line · accessed 2026-10-22