Unit 20A, Idaho

Unit 20A is severely mountainous and remote, spanning Idaho and Valley Counties, ranging from approximately 2,700 feet along the Salmon and Middle Fork Salmon River corridors to 9,258 feet at Twin Peak, with other prominent summits including Papoose (8,989 ft), Wolf Fang (8,932 ft), and Rattlesnake (7,791 ft). Most terrain is extremely steep and rugged; some drainages offer moderate grades, notably Chamberlain Basin and Whimstick Creek. The Salmon River and Middle Fork form the primary low-elevation corridors. The unit lies entirely in the Middle Fork Elk Zone (Units 20A, 26, 27) as designated by IDFG.

Unit 20A is 99.4% U.S. Forest Service land (Payette and Salmon-Challis National Forests), with 89.5% (432,526 acres) within the Frank Church-River of No Return Wilderness, where no motorized ground vehicles are permitted. All wilderness travel is by foot, horseback, or aircraft. Eight developed public-use backcountry airstrips serve the area: Bernard, Cabin Creek, Chamberlain, Cold Meadows, Indian Creek, Mahoney, Soldier Bar, and Wilson Bar. The Chamberlain Basin Guard Station (Krassel Ranger District, Payette NF) is staffed late June through mid-October. Mackay Bar, on the Main Salmon River on the unit boundary, is reachable via a long rough four-wheel-drive road from Riggins in favorable conditions. Peripheral trailheads on the Payette NF include Big Creek/Smith Creek, Lick Creek, Mosquito Ridge, Missouri Ridge, Lookout Mountain, and Roosevelt Trailheads. The Salmon-Challis NF provides trailhead access from the east side. Private land constitutes only 0.19% of the unit. State of Idaho land: 0.15%; other public: 0.22%. Outfitter lodges and tent camps operate in Chamberlain Basin, Mackay Bar, and Whimstick Creek areas.

Lower mountain slopes and river benches are covered by short grasses, brush, forbs, and open rocky terrain. Middle elevations hold large grassy meadows interspersed with scattered conifers, particularly in Chamberlain Basin and Cold Meadows. North-facing and eastern slopes are heavily timbered by Engelmann spruce, subalpine fir, lodgepole pine, and ponderosa pine. Higher ridges and peaks are generally open alpine. Some slopes show fire-denuded areas with early-successional brush and forb communities. IDFG land cover data: 98.94% forest, 1.06% rangeland.

Unit 20A supports elk, mule deer, white-tailed deer, black bear, bighorn sheep, moose, mountain lion, and gray wolf. Elk in the Middle Fork Salmon River drainage hold steady but remain at low densities below management objectives, partly attributed to wolf predation pressure per IDFG 2025 hunting outlook. Mule deer are distributed throughout; populations are described as stable to slightly declining in the Salmon Region. White-tailed deer are present particularly in riparian drainages. Black bears are common throughout; both resident and nonresident second tags and nonresident reduced-price tags are available, reflecting a liberal bear management designation. Rocky Mountain bighorn sheep occupy cliff and alpine areas (controlled hunt draw only). Mountain lions range widely; a second lion tag may be used in Unit 20A. Gray wolves maintain resident packs; wolf hunting season on public land runs Apr 1-Nov 14 (general rules) and Nov 15-Mar 31 (expanded methods allowed), with trapping subject to ongoing federal court orders affecting portions of the unit. Steelhead and trout are present in the Salmon River and Middle Fork systems.