Idaho Rocky Mountain Bighorn Sheep

Unit 20 (Salmon / Lemhi Mountains)

Idaho Hunting Guide — Rocky Mountain Bighorn Sheep

Unit 20 covers the Salmon and Lemhi Mountains of central Idaho — a dramatically scenic high-country landscape where Rocky Mountain bighorn sheep occupy open alpine ridgelines, rocky cirques, and canyon rims above the Salmon River valley. The unit is accessed from the Salmon River corridor and the Lemhi Valley to the east. Tags are extraordinarily rare, and the unit's bighorn population is carefully managed to sustain healthy, genetically diverse herds.

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Rocky Mountain Bighorn Sheep Hunting in Unit 20

Where to Find Rocky Mountain Bighorn Sheep in Unit 20

Sheep in Unit 20 are found throughout the high Salmon and Lemhi Mountains, typically above 7,000 feet during the hunting season. Focus your scouting on the alpine and subalpine zones.

Lemhi Range Ridgelines

The Lemhi Range's rocky spine supports bighorn on both flanks. Glass the west-facing slopes above the Salmon River drainage and the east-facing slopes above the Lemhi Valley from high vantage points. Sheep congregate near rocky cliff bands that provide escape terrain adjacent to open feeding slopes.

Alpine Cirques and Basins

High cirque basins in the Salmon Mountains hold sheep during the early hunting season when alpine grasses are still available. Approach these basins from ridgeline saddles to glass without alarming sheep on the basin floor.

How to Hunt Rocky Mountain Bighorn Sheep in Unit 20

Unit 20 bighorn hunting is high-altitude work — most sheep habitat is above 7,500 feet and a successful stalk requires fitness and careful planning.

Two-Side Glassing Strategy

The Lemhi Range allows hunters to glass from both the Salmon River side (west) and the Lemhi Valley side (east), effectively doubling your coverage. Drive the Lemhi Valley road and glass west into the peaks; then drive Salmon River access roads and glass east. Locate rams from the road before committing to a pack trip.

Glassing Light and Weather Windows

Sheep are most active feeding in the early morning and late afternoon. Post-storm clearing is an excellent time to glass — sheep often emerge from sheltered terrain to feed aggressively on exposed rocky slopes after a weather system passes.

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Rocky Mountain Bighorn Sheep Success Rates

Unit 20 tag holders achieve success rates of approximately 65–80% over a full hunt. The Lemhi and Salmon mountain terrain offers quality rams, and hunters who plan extended expeditions of 10+ days perform best.

Rocky Mountain Bighorn Sheep Draw Odds

Season	Tags	Applicants	Draw %	Pts Req
Rifle— Controlled	2	37	5.4%	0

Data from 2025 draw results. Resident odds shown.

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Draw odds for Unit 20 bighorn tags are under 1% for residents in most years. The unit issues only a handful of tags annually, and applicant pools are large. Bonus point accumulation over 15–20+ years is typically required.

Frequently Asked Questions

What elevation do sheep occupy in Unit 20 during hunting season?

Bighorn sheep in Unit 20 are typically found between 7,000 and 10,000 feet elevation during the fall hunting season. They descend to lower canyon terrain in deep winter but are concentrated at alpine and subalpine elevations during the hunt window.

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Sources & Verification

Every fact on this page is tied to a primary source below. Last fact-checked 2026-04-18.

IDFG Big Game Rules — Idaho Department of Fish and Game · supports: Unit boundaries, Season structure, Tag quotas · accessed 2026-04-18
IDFG Big Game Hunting — Idaho Department of Fish and Game · supports: Species info, Draw system, License requirements · accessed 2026-04-18