Unit 60, Idaho

Unit 60 spans roughly 280,376 acres across two dominant landform types: the nearly-flat Island Park Caldera floor (formed by volcanic eruptions ~1.3 million years ago), which sits at approximately 6,300–6,500 feet elevation, and the rugged Centennial Mountains rising along the Montana border with peaks including Sawtell Peak (9,886 ft), Targhee Peak (10,240 ft), and Mount Jefferson (10,203 ft). The caldera floor is relatively gentle with less than 20% slope across most of its area, while the Centennial Range delivers steep ridgelines, dense timber, and high alpine basins. The Henrys Fork (North Fork) Snake River and its many spring-fed tributaries — including Big Springs — drain the caldera.

Primary vehicle access runs via U.S. Highway 20, which bisects the caldera north-south from Ashton to the Montana state line near West Yellowstone. State Highway 87 extends northwest toward Montana. The unit boundary is generally defined by the Spencer-Kilgore Road on the west, U.S. 20, State Highway 47 southeast to North Hatchery Butte Road, then east along Fish Creek Road to the Yellowstone Park boundary, and west along the Montana state line to Monida Pass at I-15. Forest roads off Highway 20 provide backcountry access into the Centennial Mountains. The Caribou-Targhee National Forest (Ashton/Island Park Ranger District) manages 37% of Unit 60. Harriman State Park (Wildlife Refuge) within the unit is closed to hunting. Chester Wetlands WMA has short-range weapons restrictions. No federally-designated wilderness areas fall within Unit 60 proper. Grizzly bear activity is documented throughout the unit. Land ownership: USFS 37.1%, Private 31.0%, State of Idaho 17.9%, BLM 11.9%, Bureau of Reclamation 1.5%.

The unit transitions from dense lodgepole pine forest dominating the caldera floor and mid-elevation slopes, to subalpine fir and Engelmann spruce at higher elevations in the Centennial Range. Aspen groves appear in drainages and burns. Open meadows and sagebrush-grass flats occur throughout the caldera, while montane sagebrush-steppe habitat occupies drier portions and the unit's western and southern margins. Wetland and riparian habitat along the Henrys Fork and its tributary spring systems adds significant diversity. Land cover is approximately 42% forest and 43% rangeland/grassland per IDFG unit data.

Unit 60 supports elk (part of the Island Park Elk Zone herd managed across Units 60, 60A, 61, 62, and 62A), mule deer, white-tailed deer, moose, pronghorn antelope, black bear, mountain lion, and gray wolf. Recent surveys found Island Park zone elk numbers well above management objectives, prompting expanded hunting opportunities for 2025. Elk follow seasonal migrations: summer range in the Centennial Mountains along the Idaho-Montana border, with animals moving south and west to valley wintering areas in the Sand Creek Desert as winter snowpack builds. Moose are present year-round in riparian and wetland habitats along Henrys Fork and its tributaries. Pronghorn occur in open sagebrush flats and rangeland in Clark County to the west. Grizzly bears are present throughout; gray wolf packs are active, subject to an Island Park Zone harvest limit of 30 wolves. Sandhill cranes, sage-grouse, sharp-tailed grouse, and forest grouse also inhabit the unit.