Unit 501, Colorado

Elevation ranges from approximately 6,880 feet on the South Park grassland floor to 12,335 feet at the highest points in the Tarryall and Kenosha ranges. The mountain fringe is characterized by rugged, highly dissected terrain of rounded granite domes, rare granite arches, long canyons, and numerous creek drainages; the Lost Creek Wilderness section averages 8,000–12,400 feet. The central portion of the unit is the broad, relatively flat South Park basin. The 2002 Hayman Fire burned a significant portion of the forested fringe, creating large swaths of open, regenerating terrain within the Pike National Forest. 4WD is recommended on many secondary Forest Service roads.

The unit is managed primarily by Pike-San Isabel National Forest, South Platte Ranger District (approximately 287,000 USFS acres per GoHunt; ~89% of unit area). Access highways form the unit boundary: US 285 on the west and south (Fairplay-to-Denver corridor), US 24 on the east, and Park County Road 77 on the north/northeast. Dispersed camping is available along Forest Service roads throughout the unit. The Lost Creek Wilderness (119,790 acres, with approximately 136 miles of trails including 105 miles within the wilderness boundary) prohibits motorized equipment and mechanized vehicles; wilderness permits are self-issued free at trailheads. Special regulation: the McArthur Gulch area (480 acres) prohibits centerfire rifle hunting. Tarryall Reservoir (711 acres) is a notable interior landmark. The small community of Guffey lies near the unit. Hayman Fire-affected Forest Service lands have extensive road closures during wet conditions and several secondary roads require high-clearance 4WD. Recreational pressure is high near trailheads due to proximity to the Denver metro area. Private land constitutes roughly 6–9 percent of the unit, concentrated in the South Park basin floor.

Vegetation is strongly elevation-stratified. Above 11,500 feet: alpine tundra (sedges, forbs, willows). Between 9,000–11,500 feet: spruce-fir and mixed conifer with interspersed aspen stands. At mid-elevations: ponderosa pine, Douglas-fir, and riparian cottonwoods along drainages. Post-Hayman burn areas support dense oakbrush and young aspen regeneration that provide exceptional browse. The South Park basin floor supports shortgrass prairie and sagebrush shrubland, covering nearly one-third of the unit and supporting pronghorn. Riparian corridors run along the South Platte River, North Fork of the South Platte, Tarryall Creek, and Lost Creek.

The unit supports elk, mule deer, pronghorn antelope, Shiras moose, black bear, mountain lion, and wild turkey. Elk summer in the high-elevation wilderness terrain and conifer forests, moving to mid-elevation and lower-country winter range in late fall; forum reports indicate most elk use private lands in the South Park basin as fall progresses, making public-land elk hunting in the wilderness and burn areas the productive early-season strategy. Mule deer follow a similar elevation-driven seasonal movement. Pronghorn concentrate on the open grasslands of South Park year-round, with bucks often visible on the basin flats; South Park supports one of Colorado's highest-elevation pronghorn herds with the rut running early September through mid-October. Shiras moose are present but sparse, concentrated in willow riparian corridors within the Lost Creek Wilderness drainages and adjacent low-elevation draws. Black bear are active throughout the forested mountain fringe and Hayman burn areas during summer and early fall prior to denning. Mountain lion follow deer and elk populations through the rugged canyon and granite terrain.