Unit 37, Idaho

Unit 37 encompasses a dramatic elevation range from roughly 4,600 feet at the Salmon River confluence to over 12,000 feet in the Lost River Range (Borah Peak, Idaho's highest summit at 12,662 feet, lies on the unit's western fringe). The Pahsimeroi Valley bisects the unit, rising from approximately 4,600 feet at its lower end to about 7,800 feet near the divide with the Little Lost River drainage. Terrain transitions sharply from broad, irrigated valley floors to steep canyon walls, rugged foothills, and rocky alpine ridgelines. Four-wheel drive is recommended on canyon roads; the high country above 8,000 feet is predominantly roadless.

Unit 37 is bounded by U.S. Highway 93 on the south and west (between the Salmon River bridge south of Challis and Willow Creek Summit) and by the Ellis-May-Howe Highway on the north. The Pahsimeroi Valley Road provides the primary spine of access from the south (U.S. 93 near Mackay) northward through the valley toward the Ellis-May-Howe Highway junction. Most roads in the unit are open to all motor vehicles, though off-road travel is prohibited. A critical motorized-hunting rule (applicable August 30–December 31) restricts all motor vehicles to established roadways open to full-sized automobiles for big game hunters. High-country access to Salmon-Challis National Forest trailheads is primarily via Forest Service roads branching from canyon side-drainages on the flanks of the Lost River and Lemhi Ranges. The Challis-Yankee Fork Ranger District (Challis, ID; 208-879-4100) administers forest lands within the unit. There are no federally designated wilderness areas within Unit 37 itself, though the Frank Church–River of No Return Wilderness lies immediately to the north and northwest. Access to private land can be constrained in the lower Pahsimeroi Valley, where irrigated ranch lands dominate. No Idaho Department of Fish and Game Access Yes! properties are currently enrolled in Unit 37. Nearest services are in Challis (approximately 30 miles southwest via U.S. 93).

Valley floors and lower foothills support sagebrush-steppe, native bunchgrasses, and irrigated agricultural fields that attract wintering elk and deer. Mid-elevation slopes (roughly 6,000–9,000 feet) transition through mountain mahogany, curl-leaf mahogany, juniper, ponderosa pine, and Douglas-fir. Higher elevations carry lodgepole pine, Engelmann spruce, and subalpine fir, grading into open rocky slopes and alpine meadows above timberline. Riparian corridors along the Salmon and Pahsimeroi Rivers support willow, cottonwood, and associated shrubs that provide year-round cover for mule deer, moose, and upland birds.

Mule deer are the primary deer species, occupying sagebrush foothills and mountain slopes; they migrate from high summer range down to lower valley elevations as winter approaches. Elk populations split between mountain elk that summer on high ridgelines and canyon drainages above 8,000 feet, and a valley herd that frequents irrigated agricultural fields on and near private ranches in the Pahsimeroi Valley; movements can be rapid and vertical. California bighorn sheep (Ovis canadensis californiana) occupy rocky canyon walls and ridgelines in the Lost River and Lemhi Range faces; IDFG conducts active population monitoring in the Pahsimeroi Valley for this herd. Pronghorn are present in the lower valleys and open sagebrush flats. Black bear and mountain lion roam the forested mid-elevations and canyon systems. Gray wolves are present in the Salmon Region and may move through the unit. Moose utilize riparian drainages and willow corridors. Upland birds including chukar, Hungarian partridge, forest grouse, sage-grouse, sharp-tail grouse, pheasant, turkey, and California quail are confirmed present across various elevations per IDFG unit data. The Salmon River provides steelhead and salmon fishing along the unit's western boundary.