Moose can be found on mountains, in canyons, brushy draws, in marshy areas and along creek and river bottoms in this unit around Mackay.

Moose are common and the terrain is steep enough and open that hunters rarely fail to find bulls.

Big Lost River and Thousand Springs valleys are in this unit as well as the mountains on both sides of them. The valleys are flat with dry and wet creek beds and ravines running through them and foothills on their sides. The valleys run from 5,500 to 6,500 feet above sea level. The White Knob Mountains are in the Salmon-Challis National Forest along with part of the Salmon River Mountains and the north side of the Pioneer Mountains. All three ranges are mostly steep, but some big basins, valleys and mild terrain such as the Copper Basin and the Sawmill Creek bottoms can be found here. The northern and western boundaries are in the Lost River Range, which is high, rugged and steep in places. High points include Idaho’s highest peak, Borah Peak, and several other 12,000-foot-plus peaks in the Lost River Range. Many peaks exceed 9,000 feet in the western half of the unit, including Standhope Peak.

Timberline varies from about 9,000 to 9,500 feet. Above the timberline lichens, mosses, low shrubs and wild grasses on thin soils can be found. The highest trees are sparse firs, pines and spruces. Below them are dense conifer forests. Lower forests have Douglas firs, Engelmann spruce, aspen and ponderosa pines. Some junipers and mahoganies grow on some foothills and low ridges and in some draws. The foothills below timber are covered with sagebrush and wild bunchgrass. Private lands are rangeland and farm land, which is mostly planted in hay. Many alfalfa fields are irrigated by pivot sprinklers.

Most of the mountains are in the Salmon-Challis National Forest, while foothills are primarily on BLM land. About a dozen state parcels, most of them 640 acres apiece, are scattered in the foothills. Several public-access roads cross private ground to reach the foothills and mountains. The main road is U.S. Highway 93. Several branch from U.S. 93 access the mountains or branch into access roads, such as Mine Hill Road up Rio Grande Canyon west of Mackay. Trail Creek Road provides good access in the northwestern part of the unit and leads to several other roads that penetrate the interior.

Most hunters camp along dirt roads or in Forest Service campgrounds. The Forest Service has several campgrounds, such as Park Creek Campground. A campground at Mackay Reservoir is close to mountains on both sides of the Big Lost River. Several private campgrounds are in or near Mackay. Lodging is available in Mackay and Arco. In Mackay are The Bear Bottom Inn and Wagon Wheel Motel, which also has an RV park, as does White Knob Motel. Arco Inn Motel is on the southern edge of the unit.