Unit 50

Prominent summits including Arco Peak, Mackay Peak, Timbered Dome, and the White Knob Mountains provide distant orientation and glassing vantage points. The Pahsimeroi Mountains and Boulder Mountains form major ridgelines. Key water features—Betty Lake, Wildhorse Lakes, Boulder Lake, and the numerous springs scattered throughout—anchor drainage systems.

Distinctive formations like The Needles and Cave Rock offer visual reference points. Named drainages including Park Creek, Deer Creek, and Twin Bridges Creek provide navigation corridors through otherwise subtle terrain.

Terrain ranges from mid-elevation valleys near 5,200 feet to alpine summits exceeding 12,500 feet, with most country sitting in the 7,000 to 9,500-foot band. Open sagebrush basins and flats dominate the lower and middle elevations, with scattered juniper and mountain mahogany providing sparse woody cover. Higher elevations support patchy stands of whitebark pine and subalpine fir, though timber remains sparse throughout.

The landscape is fundamentally sagebrush country broken by rock outcrops, lava flows, and scattered canyons that funnel into larger drainages.

Over 2,200 miles of roads connect the unit, creating fair accessibility despite the vast terrain. Multiple entry points from surrounding towns allow hunters to stage from Arco, Mackay, or smaller communities, distributing pressure across drainages. However, the terrain's complexity means distance from trailheads increases quickly once you leave roads.

The sagebrush expanse can appear featureless, making it easy to miss subtle draws and ridgelines that concentrate game. Early-season and weekend pressure concentrates near road-accessible flats; solitude increases significantly in remote basins.

Unit 50 encompasses large portions of Blaine, Butte, and Custer counties, bounded by U.S. 20-26 to the south and west, the Big Lost River drainage to the north, and the Camas Creek watershed divide to the east. The unit straddles the Anderson Ranch Reservoir area and extends up the South Fork Boise River and Lime Creek drainages. Towns including Arco, Mackay, and Chilly frame the surrounding region.

This sprawling unit captures multiple mountain ranges and high-desert basins across a geographically complex area with a long hunting history.

Water is the limiting factor in Unit 50. The Big Lost River system, Anderson Ranch Reservoir, and scattered alpine lakes provide reliable sources in upper basins, but much of the sagebrush country relies on springs and seasonal seeps. Named springs include Slaughterhouse Springs, Scratching Post Spring, and Walker Spring, though their reliability varies seasonally. The South Fork Boise River and Lime Creek drainage systems hold water year-round in their upper reaches.

Low-elevation flats and basins often run dry mid-season, making higher-elevation water sources critical for extended hunts.

This is pronghorn country, and the unit's open sagebrush basins provide ideal habitat for spotting and stalking. The elevation gain and ridge systems allow glassing from distance to locate animals before closing distance. Early season offers the best opportunity, as herds move between basins and aren't yet concentrated in refuge areas.

Water sources, while limited, become focal points late season. Hunt high ridges for wind and visibility, then work down into basins and canyons where pronghorn feed and bed. The sprawling size means success often comes to hunters willing to glass methodically and cover country on foot rather than road-hunting.