Colorado Unit S66 Bighorn Sheep Hunting Guide

Colorado Unit S66 is a limited-quota bighorn sheep unit tucked into some of the highest, most rugged terrain in the state, with elevations ranging from 8,251 feet to 14,422 feet across 177,524 total acres. For hunters chasing one of the most coveted tags in North American big game hunting, S66 represents a genuine opportunity — but understanding the structure of this unit, its harvest trends, and its access realities is essential before investing points or planning a season around it.

Unlike deer or elk units where a general season provides a fallback option, bighorn sheep hunting in Colorado — including in S66 — runs entirely through limited-quota draw hunts. There is no general season here. Every ram tag, and every hunt available in this unit, comes through the draw. That structure alone tells hunters most of what they need to know about how competitive and how managed this resource is.

With 89% of the unit in public ownership and 36% classified as wilderness, S66 offers substantial access for hunters willing to put in the physical effort that alpine sheep hunting demands. This is not a drive-to-the-trailhead-and-glass-from-the-truck unit. It's high-altitude, foot-and-optics country, and the data backs that up.

HuntPilot Analysis: Is S66 Worth Applying For?

The honest answer is: it depends on what a hunter is looking for, and how much point equity they're willing to spend.

Looking at harvest data compiled by HuntPilot across the last several seasons, S66 has produced consistently strong success rates for a limited-entry sheep unit. In 2023, 20 hunters harvested 16 rams for an 80% success rate — an exceptional number for any alpine bighorn hunt. That wasn't a fluke; 2019 saw 9 hunters post an 89% success rate, and 2021 recorded 75% success on 16 hunters. Even the "softer" years in this data set — 2022 and 2025 — still posted 60% success. Across the seven years of harvest data available, success rates never dropped below 60%. That is a remarkably stable trend line for a species notorious for tough, low-percentage hunts in other units and other states.

What that tells hunters is straightforward: if you draw a tag in S66, the odds of putting a ram on the ground are good relative to bighorn hunting generally. This isn't a unit where hunters commonly go home empty-handed after burning a once-in-a-lifetime tag. The terrain is demanding, but the sheep are apparently locatable and huntable within the season framework in place.

On trophy quality, hunters should manage expectations carefully. The counties overlapping this unit carry a limited history of trophy-class record entries. That doesn't mean rams here can't be mature, full-curl animals — it means the documented trophy pedigree is thin compared to some of Colorado's more storied sheep units. Hunters chasing a top-tier score for the record books should treat S66 as a unit where the hunt experience and success-rate math are the draw, not a guaranteed shot at a unit-record ram.

Tag quotas here are also worth understanding before applying. Quotas are broken out by specific hunt codes, and they move independently of each other year to year — there's no unit-wide trend to lean on. One hunt code saw its quota cut sharply from 2025 into 2026, while another hunt code saw a meaningful increase over the same period, and a third has held flat across all three years shown. This tells hunters that S66's tag numbers are actively managed and can shift significantly from one cycle to the next, reinforcing the need to check current quotas directly before building an application strategy around a specific hunt code.

Given the wilderness percentage (36%) and the overall ruggedness implied by the elevation range, S66 rewards hunters who are physically prepared for sustained work above 9,000 feet, and often above 12,000 feet, over extended periods. This is consistent with what sheep hunters have reported anecdotally about Colorado's high-country units generally — camps and glassing routines built around alpine basins, not roadside hunting.

Bottom line: S66 is worth applying for if a hunter's priority is a realistic chance at filling a bighorn tag in demanding, majority-public terrain, and if trophy score is a secondary consideration to the experience and the fill rate. It's less compelling for hunters whose primary goal is chasing a unit with a deep trophy record history.

Harvest Success Rates

S66's harvest data spans seven recorded seasons and shows some of the more consistent success numbers a hunter will find in bighorn sheep hunting:

• 2025: 10 hunters, 6 harvested — 60% success
• 2024: 20 hunters, 14 harvested — 70% success
• 2023: 20 hunters, 16 harvested — 80% success
• 2022: 20 hunters, 12 harvested — 60% success
• 2021: 16 hunters, 12 harvested — 75% success
• 2020: 12 hunters, 8 harvested — 67% success
• 2019: 9 hunters, 8 harvested — 89% success

Across these seven years, success rates ranged from a low of 60% to a high of 89%, and never dipped below 60% in any single season. Hunter numbers have also varied, from as few as 9 to as many as 20 in a given year, which lines up with the shifting tag quotas seen in the hunt-code-level data. For hunters weighing whether to spend points on S66, this track record suggests that drawing a tag here has historically translated into a strong chance of filling it — a meaningful data point when comparing this unit against other Colorado bighorn options.

Trophy Quality

Trophy data for S66 is limited. The counties overlapping this unit carry only a limited history of trophy-class record entries, which points to limited trophy potential rather than a unit with a deep pedigree of record-book rams. Hunters should not expect S66 to compete with Colorado's premier trophy sheep units in terms of documented big-ram history.

That said, a limited trophy record doesn't necessarily mean small sheep — it more often reflects fewer tags issued over time, less hunting pressure generating fewer measured entries, or simply a unit that hasn't built the same reputation as neighboring drainages. Hunters should treat S66 as an opportunity-and-experience unit first, with trophy potential as a secondary, unproven variable.

Access & Terrain

S66 sits almost entirely on public ground, with 89% public land ownership across its 177,524 acres. That level of access is a significant advantage for hunters who don't want to negotiate private land permissions or work around checkerboarded ownership — the vast majority of this unit is open to hunt without additional landowner arrangements.

The terrain itself is defined by extreme vertical relief. Elevations run from 8,251 feet at the unit's lowest points up to 14,422 feet at its highest — a range that places much of the huntable sheep habitat well above treeline, in alpine basins, talus fields, and exposed ridgelines typical of Colorado's highest peaks. With 36% of the unit designated wilderness, a substantial portion of S66 is also subject to wilderness travel restrictions — no mechanized or motorized access, which means hunts in those areas are conducted entirely on foot or horseback.

Colorado does not impose the nonresident guide requirement that some western states mandate for wilderness hunting, so nonresident hunters are free to hunt the wilderness portions of S66 without hiring an outfitter. That said, the combination of elevation, exposure, and distance from roads in the wilderness-designated portions makes this genuinely demanding country. Hunters should plan for extended pack-in logistics, be prepared for rapid weather changes at elevations exceeding two miles above sea level, and factor significant acclimatization time into any hunt plan, particularly for hunters traveling from lower elevations.

Given the public land percentage, DIY hunters have ample legal access to hunt this unit without needing to secure private ground — but that access comes with the physical cost of alpine terrain that doesn't offer many shortcuts.

How to Apply

Bighorn sheep tags in Colorado, including every hunt available in Unit S66, are issued exclusively through the state's limited-quota draw system — there is no over-the-counter or general season option for this species in this unit. Both resident and nonresident hunters must apply through Colorado Parks and Wildlife's draw process to be eligible for a tag here.

Colorado's draw operates on a preference point system, meaning hunters accumulate points in years they aren't drawn, and the state's highest point holders draw first in a portion of the available tags. A high enough point level can effectively guarantee a tag on some hunts, though this varies significantly by hunt code and by year. Because S66's tag quotas are broken out by specific hunt codes — and those quotas have moved independently and sometimes dramatically between recent cycles — hunters should check current, hunt-code-specific draw data before assuming any particular point level is sufficient.

Residents and nonresidents apply through the same general draw structure in Colorado, though tag allocations and competitiveness can differ between residency categories. Successful applicants who draw a tag will see their preference points reset, so hunters re-entering the draw after a successful hunt should expect to rebuild point standing from scratch.

Application windows, fees, and current point requirements change every cycle, so hunters should not rely on prior-year numbers when planning. For the most current deadlines, fees, and draw odds for Unit S66, see HuntPilot's Colorado state page at /states/CO, which pulls updated figures directly from the state's published draw data.

Frequently Asked Questions

What is the terrain like in Colorado Unit S66? S66 is extreme high-alpine country, with elevations spanning from 8,251 feet to 14,422 feet across 177,524 acres. A significant share of the unit — 36% — is designated wilderness, meaning no motorized or mechanized access in those areas. Expect steep, rocky, above-treeline terrain typical of Colorado's highest peaks, reachable primarily on foot or horseback.

What is harvest success like in Unit S66? Harvest success in S66 has been strong and consistent. Across seven recorded seasons from 2019 through 2025, success rates ranged from 60% to 89%, with most years landing between 60% and 80%. This is a notably reliable fill rate for a bighorn sheep unit, suggesting that hunters who draw a tag here have a good historical chance of connecting.

How big are the bighorn sheep in Unit S66? Trophy data for S66 is limited — the counties overlapping this unit have only a limited history of documented trophy-class record entries. This points to limited trophy potential compared to some of Colorado's more established sheep units, though the unit's strong harvest success suggests mature, huntable rams are present and being taken regularly.

Is Unit S66 worth applying for? For hunters prioritizing a realistic chance at filling a bighorn tag in mostly public, high-alpine terrain, yes — the harvest data supports that S66 is a productive unit relative to bighorn hunting broadly. Hunters specifically chasing a unit with deep trophy pedigree may want to weigh that priority against S66's more limited documented trophy history before committing points here.

Does Unit S66 have a general season for bighorn sheep? No. Every bighorn sheep hunt in Unit S66 is issued through Colorado's limited-quota draw system. There is no general or over-the-counter option for this species in this unit — all hunters, resident and nonresident alike, must draw a tag to hunt here.