Idaho Rocky Mountain Bighorn Sheep

Unit 21L (Lost River Range — Archery)

Idaho Hunting Guide — Rocky Mountain Bighorn Sheep

Unit 21L is the archery-only limited permit for the Lost River Range — identical terrain to the rifle Unit 21 but demanding bowhunting at close range from some of Idaho's most spectacular high alpine landscapes. Drawing this tag represents a rare chance to pursue Rocky Mountain bighorn sheep with stick and string in the shadow of Borah Peak. The archery season's earlier timing means sheep are still in summer range patterns before the November rut.

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Rocky Mountain Bighorn Sheep Hunting in Unit 21L

Where to Find Rocky Mountain Bighorn Sheep in Unit 21L

During the archery season, sheep in Unit 21L are at their highest elevations — focus on the upper rocky basins and ridgelines of the Lost River Range above 9,000 feet, where late summer grasses and forbs are still available.

High Cirque Basins

The high glacially carved basins on both flanks of the Lost River Range hold sheep through early fall. Glass into these basins from ridgeline saddles above — position yourself above the expected sheep locations to use thermals to your advantage.

How to Hunt Rocky Mountain Bighorn Sheep in Unit 21L (Archery)

Archery bighorn in the Lost River Range demands exceptional physical conditioning — approach routes to alpine sheep terrain require sustained climbing at high elevation, and you must close to within 60 yards under open conditions.

Pre-Dawn High Camp Strategy

Establish a high camp near sheep habitat to eliminate the daily elevation gain from valley camp. Being at elevation at first light — when sheep are actively feeding on open faces — maximizes your glassing and stalk opportunities during the archery season's limited daylight window.

Down-Canyon Wind Management

In the Lost River Range, winds typically flow up-canyon during the day and down-canyon at night. Plan archery approaches for the early morning when downslope thermals keep your scent away from sheep above you. Switch to ridge-level approaches once thermals turn upslope mid-morning.

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Rocky Mountain Bighorn Sheep Success Rates

Success rate data not yet available for this species in this unit.

Archery bighorn success in Unit 21L is challenging — expect 40–60% success rates reflecting the difficulty of closing within bow range of open-country sheep. Hunters who put in significant pre-season scouting and are comfortable glassing and stalking at altitude perform best.

Rocky Mountain Bighorn Sheep Draw Odds

Season	Tags	Applicants	Draw %	Pts Req
Rifle— Controlled	1	58	1.7%	0

Data from 2025 draw results. Resident odds shown.

Open in Draw Odds Engine

Unit 21L issues only 1–2 archery tags annually for bighorn sheep. Draw odds are fractional — this is effectively a lottery that most applicants will never win in their lifetime of applying.

Frequently Asked Questions

When does the Unit 21L archery bighorn season typically open?

Idaho archery bighorn seasons typically open in late August. Check the current IDFG Big Game Rules booklet for exact dates, as season structures can adjust from year to year based on herd data.

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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