Unit BH4

The Twin Sisters Range and its associated peaks anchor the landscape; Unkpapa Peak, Buckhorn Mountain, and Thunderhead Mountain serve as excellent navigation references and distant glassing points. The Needles and Cathedral Spires provide dramatic landmarks visible across multiple valleys. Sylvan Lake and the network of smaller lakes and reservoirs (Twin Lakes, Rogers Lake, Cameron Pond, Ward Reservoir) mark reliable water sources and natural gathering points.

Buffalo Gap cuts through the landscape as a major drainage corridor, while named flats—Hopkins, Dead Horse, and Danby Park—provide open areas useful for spotting and route planning.

Terrain primarily spans middle elevations where ponderosa pine and Douglas fir mix with open grassland parks and sagebrush flats. Most of the unit sits below 6,500 feet, with scattered ridges and peaks pushing into the upper-elevation band. This elevation distribution creates distinct habitat zones: lower parks dominated by sagebrush and native grasses, mid-slope timber providing cover and travel routes, and open rocky ridges ideal for bighorn movement and observation.

The forest density varies significantly—dense timber on north-facing slopes contrasts with sparse coverage on south-facing parks, creating diverse habitat mosaics that support year-round sheep populations.

A moderate road network (1.42 miles of road per square mile) provides fair access without overwhelming pressure. Major highways and the junction near Custer offer multiple entry points, but much of the unit requires hiking beyond maintained roads. The majority of hunters concentrate on areas near Sylvan Lake Resort and accessible ridge trailheads, creating opportunities for those willing to venture deeper into the canyon systems and northern ridges.

Public land comprises 64% of the unit, with private inholdings concentrated in lower valleys. Limited water sources naturally funnel sheep and hunting pressure toward known springs and creek bottoms, making basin bottoms and high ridge systems worth exploring during mid-day glassing.

BH4 encompasses roughly 775 square miles of the central Black Hills, one of the most productive bighorn sheep regions in the state. The unit is dominated by the Twin Sisters Range and associated ridgelines, with the town of Custer serving as the primary access point. Sylvan Lake and the surrounding park system form the geographic heart, with multiple drainages radiating outward.

The landscape transitions from lower sagebrush parks to timbered ridges, with numerous named valleys and canyons providing natural travel corridors and water sources for both sheep and hunters.

Water availability is scattered but adequate for sheep country. Multiple named springs dot the ridgelines and canyon heads: Pease Spring, Red Bank Spring, Sawmill Spring, and others provide reliable water throughout the higher terrain. Perennial and semi-reliable streams include Middle Fork French Creek, North Fork Lame Johnny Creek, Hay Creek, and Fourmile Creek—these drainages serve as primary travel corridors and water sources for bighorn.

Lower elevation parks and valley bottoms have more limited water, requiring sheep and hunters to key on identified spring locations and creek systems. Seasonal snowmelt and monsoon rains increase water availability, especially mid-summer through early fall.

Mountain sheep hunting in BH4 depends on understanding seasonal movement patterns and water dependency. Early season (late August-early September) finds bighorn in high parks and ridgelines; focus glassing on open parks above timberline and ridgetops offering vantage points over multiple drainages. Mid-season brings sheep lower toward water sources and mid-elevation timber.

Key drainages like Buffalo Gap, Sled Canyon, and Antelope Canyon become critical access routes; work quietly through these features during early and late light. Late season pushes sheep into lower parks and valley bottoms where water concentration increases. The ridge systems running north-south provide excellent all-day glassing positions; use peaks like Thunderhead and Buckhorn as basecamp locations.

Pack in for multi-day efforts to hunt less-pressured terrain away from day-use areas.