Idaho Unit 20A Bighorn Sheep Hunting Guide

Idaho Unit 20A is one of the most demanding and rewarding bighorn sheep hunts in the Northern Rockies, a backcountry unit defined almost entirely by wilderness terrain and extreme vertical relief. For hunters who manage to draw a tag here, this unit represents a true once-in-a-lifetime pursuit — the kind of hunt that requires months of physical preparation and a serious commitment to scouting before ever nocking an arrow or chambering a round.

This unit spans 483,329 acres with elevations ranging from 2,152 feet up to 9,342 feet, and every single acre is public land. That 100% public land designation means access is not the limiting factor here — terrain, physical difficulty, and tag scarcity are. With 90% of the unit classified as wilderness, this is overwhelmingly a foot-and-horseback hunt, far removed from roads and the conveniences that come with them.

Because the draw here is exclusively limited-quota — there is no general season in 20A for bighorn sheep — every hunter in the field is operating on a once-in-a-lifetime (or once-in-several-lifetimes) tag. That scarcity, combined with the unit's rugged wilderness character, shapes everything about how hunters should approach planning, scouting, and physical preparation for this hunt.

HuntPilot Analysis: Is Unit 20A Worth Applying For?

For hunters serious about bighorn sheep, Unit 20A deserves strong consideration — with some important caveats. The harvest data tells a story of a unit that consistently produces for the hunters who draw it. Success rates over the past six seasons have ranged from 35% to 56%, with the most recent 2025 season posting a 54% success rate (51 rams harvested from 94 hunters). That is a notably strong success rate for mountain sheep hunting anywhere in the West, and it suggests that hunters who do their homework and put in the physical effort have a legitimate chance at connecting.

Looking at the recent trend, success has actually been climbing: 35% in 2020, up through the mid-40s in 2022 and 2023, to 48% in 2024, and 54% in 2025. That is not a single-year spike — it's a multi-year pattern worth noting, though hunters should remember that success rate reflects hunter effort and skill as much as herd abundance. Hunter numbers have also grown modestly, from 71-72 hunters in 2021-2023 up to the mid-90s in 2024 and 2025, while harvest numbers have kept pace, which is a good sign that the resource is supporting increased hunting pressure without success collapsing.

On the trophy side, the counties overlapping this unit carry a moderate history of trophy-class ram production. This isn't an elite unit stacked with record-book entries, but it has produced quality, legal rams with some regularity over time. Hunters going into 20A should set realistic expectations: this is a hunt for a mature, legal ram in brutal, beautiful country — not necessarily a chase for a unit-record head. That said, moderate trophy history combined with a strong and improving success rate makes this a very credible option for a hunter who draws and is willing to put in serious physical effort.

The one hunt type with known quota data, hunt 5005, has seen its tag allocation increase from 3 tags in both 2023 and 2024 up to 4 tags in 2025 — a 33% increase. That is a small but meaningful bump in opportunity, and it reflects a unit where wildlife managers appear comfortable with modest growth in tag numbers given the resource and recent harvest trends.

The verdict: if a hunter draws this tag, Unit 20A is absolutely worth the investment of time, scouting, and physical preparation. The success rates justify the difficulty of the terrain, and the moderate trophy potential means hunters can expect a legitimate, respectable ram rather than a long-shot pursuit.

Harvest Success Rates

Unit 20A's harvest numbers over the past six years paint a consistent picture of a productive bighorn sheep unit:

• 2025: 94 hunters, 51 harvested — 54% success
• 2024: 98 hunters, 47 harvested — 48% success
• 2023: 72 hunters, 32 harvested — 44% success
• 2022: 90 hunters, 38 harvested — 42% success
• 2021: 71 hunters, 40 harvested — 56% success
• 2020: 112 hunters, 39 harvested — 35% success

Across these six seasons, success has ranged from a low of 35% in 2020 to a high of 56% in 2021, with the two most recent years (2024 and 2025) both landing in the upper-40s to mid-50s range. This is a meaningfully strong track record for mountain sheep hunting, where success often hinges on physical conditioning, weather windows, and the ability to close distance in extremely steep, remote terrain. Hunters drawing this tag should feel confident that, historically, roughly half of those who hunt this unit connect on a ram — but that figure also reflects hunters who are typically well-prepared given the rarity and value of a bighorn tag.

Trophy Quality

Trophy records from the counties overlapping Unit 20A reflect a moderate history of production — not an elite trophy unit in the record-book sense, but a unit that has reliably put legal, mature rams in hunters' hands over time. Given that the same county-level trophy data is shared across neighboring units in this region, hunters should view this as a regional indicator rather than a unit-exact guarantee of trophy size.

Hunters should enter this hunt with realistic goals: find a mature, legal ram and be prepared to work extremely hard in wilderness terrain to do so. The data does not support an expectation of chasing a potential state-record animal, but it also does not suggest a unit of marginal rams. Moderate trophy potential paired with strong recent success rates is a solid combination for a hunter focused on the overall experience and a respectable, hard-earned ram.

Access & Terrain

Access and terrain are the defining characteristics of Unit 20A, and hunters need to understand this before investing in scouting trips or physical training.

With 100% public land, there are no private land access issues to navigate — every acre of this 483,329-acre unit is open to hunters who draw a tag. That is a significant advantage over many Western big game units where checkerboard ownership or locked gates limit where hunters can actually go.

However, the 90% wilderness designation is the critical factor that shapes this entire hunt. The vast majority of this unit is accessible only by foot or horseback — no roads, no motorized access, no shortcuts. Combined with an elevation range stretching from 2,152 feet at the lowest points to 9,342 feet at the highest, hunters are looking at some of the most extreme vertical relief found in any Idaho big game unit. This is backcountry sheep country in the truest sense: steep rock, exposed basins, and long approaches that require real physical capability and backcountry logistics experience.

Hunters planning a trip into 20A should expect multi-day pack-ins, whether on foot or with stock, and should plan scouting trips well in advance of the season to understand water sources, bedding areas, and travel routes specific to the drainages they intend to hunt. Because Idaho residency does not change the wilderness access rule the way it does in some other states, all hunters — resident and nonresident alike — face the same demanding terrain and remote access challenges here. Hunters should use HuntPilot's mapping tools to study the public land boundaries and wilderness overlay for this unit in detail before committing to specific drainages, since the terrain here punishes poor planning more than almost any other Western big game hunt.

How to Apply

Idaho's bighorn sheep hunts, including Unit 20A, are allocated entirely through a limited-quota draw system — there is no general season option for this species in this unit. Every tag, for any sex class offered, comes through the application process.

Idaho's draw system does not use preference points or bonus points in the way many neighboring states do; instead, Idaho bighorn sheep tags are awarded through a random drawing process where every applicant in a given pool has an equal chance regardless of how many years they have applied. This means a first-time applicant and a hunter who has applied for a decade face identical odds in any given year's draw for this unit. There is no benefit to "building points" in Idaho because there is no point system to build — hunters should apply every year they're interested, since each year represents an independent chance.

Residents and nonresidents apply through separate pools, and because bighorn sheep tags are extremely limited nationwide, nonresident demand for Idaho sheep tags is typically very high relative to the small number of tags available.

Because application structures, tag numbers, and procedures can shift from year to year, hunters should go directly to HuntPilot's Idaho state page for the most current application windows, fees, and procedural details rather than relying on secondhand information. For year-specific quota numbers beyond what's referenced here, check HuntPilot's unit page for Unit 20A directly.

Frequently Asked Questions

What is the terrain like in Idaho Unit 20A? Unit 20A is defined by extreme vertical relief and wilderness access. Elevations range from 2,152 feet to 9,342 feet across 483,329 acres, and 90% of the unit is designated wilderness. This means hunters are dealing with steep, rugged mountain terrain accessible primarily by foot or horseback, with no significant road access into the core hunting areas. It is physically demanding country that rewards strong physical conditioning and backcountry experience.

What is harvest success like in Unit 20A? Harvest success has been strong and trending upward in recent years. The 2025 season produced a 54% success rate (51 rams from 94 hunters), following 48% in 2024. Over the past six seasons, success rates have ranged from 35% to 56%, making this one of the more productive bighorn sheep units in terms of hunters converting tags into harvested rams.

How big are the bighorn sheep in Unit 20A? Trophy records from the counties overlapping this unit indicate moderate trophy potential — this is not considered an elite record-book unit, but it has a history of producing legal, mature rams. Hunters should set expectations around harvesting a solid, respectable ram rather than chasing a potential record-class head.

Is Unit 20A worth applying for? For hunters who draw a tag here, yes — the combination of strong, improving success rates (consistently in the 40-50%+ range in recent years), 100% public land access, and moderate trophy potential makes this a legitimate, worthwhile bighorn sheep hunt. The primary challenge is the extreme terrain and wilderness access, which demands serious physical preparation, not the quality of the hunting opportunity itself.

Does Unit 20A require a guide for nonresident hunters? Idaho does not impose a guide requirement for nonresident hunters in wilderness areas the way some other Western states do. However, given that 90% of this unit is wilderness terrain with extreme elevation change and no significant road access, both resident and nonresident hunters should strongly consider the logistics of a DIY pack-in versus hiring local knowledge, even if it is not legally mandated.