Unit 521 is a Gunnison County subunit covering the Ohio Creek drainage and the country between Gunnison and Crested Butte west of CO-135—high broken ranch-and-timber country in the heart of the Gunnison Basin. Elevations climb from about 8,000 feet in the Gunnison valley near Gunnison and Almont to over 12,000 feet on the higher ridges of the Anthracite Range and Ruby Range on the western boundary. The terrain is the classic Gunnison Basin profile: broad sage-and-grass parks in the valleys with willow-bottom riparian along Ohio Creek and the East River, climbing through aspen groves on the cooler aspects (the Ohio Creek aspen burn in late September is one of Colorado's quiet visual triumphs), Douglas fir and lodgepole pine on the mid-slopes, dense subalpine spruce-fir on the higher reaches, and alpine tundra above 11,500 feet treeline. Mule deer and elk both produce well; black bear is good in the aspen-and-oakbrush; mountain lion hold the country. Gunnison National Forest covers the higher country with the Raggeds Wilderness boundary along the western and northern edges (motorized prohibited in the wilderness). Significant private deeded ranchland covers the valley floor along Ohio Creek and the East River—legacy ranch ground that locks up some of the best winter range. CO-135 runs north-south between Gunnison and Crested Butte; Ohio Creek Road (CR-730) climbs west into the timber and is the main access into the unit's interior. Gunnison is full service for fuel, food, lodging, processors, and gear; Crested Butte north is similar at higher resort prices. Cell service is poor across most of the unit—a real factor for safety. Pressure on the Gunnison Basin elk range is heavy on accessible ground; pack-in hunters find solitude.