Unit 421, Colorado

Elevation spans from approximately 4,800 ft in the Colorado River and Plateau Creek canyon bottoms up to roughly 11,000 ft on the Grand Mesa plateau. The unit encompasses rugged canyon terrain along Plateau Creek and Divide Creek drainages transitioning to the broad, relatively flat Grand Mesa top. Slopes are steep in the lower canyon zones; the mesa top is rolling high-country. Four-wheel drive is recommended on forest roads as conditions can deteriorate rapidly with rain or snow.

Primary highway access is Colorado State Highway 65 (Grand Mesa Scenic Byway), which bisects the unit from the Colorado River corridor up onto the mesa top and forms the western boundary of the GMU. Interstate 70 and the Colorado River corridor bound the unit to the north. The town of Collbran (Mesa County) on County Road 330 provides the main eastern-approach corridor, with County Roads 330E and 342 connecting to forest roads. Vega State Park and Vega Reservoir lie within the unit near Collbran, serving as a hub for access into national forest land to the west and north. The Divide Creek and Buzzard Creek drainages form the eastern boundary with adjacent GMU 42. Public land in the unit is predominantly GMUG National Forest (Grand Valley and Collbran Ranger Districts). Some BLM land is present in the lower Plateau Creek canyon. Private land exists throughout the lower-elevation agricultural areas and is not always posted; hunters must verify boundaries independently. No designated wilderness areas fall within the unit, but much of the mesa top roadless country requires foot or horseback travel to access productive habitat away from roads. Seasonal road closures apply to many forest roads during mud season (typically spring) and after heavy snowfall in late autumn.

Lower elevations (below ~7,000 ft) support pinyon-juniper and sagebrush shrublands in the canyon breaks. Mid-elevations (7,000–9,500 ft) transition into oakbrush, serviceberry, and mountain shrub communities with aspen groves that provide dense thermal cover. The Grand Mesa top (9,500–11,000 ft) is dominated by spruce-fir forests interspersed with high mountain meadows, willow-lined streams, and numerous lakes. Riparian corridors follow Plateau Creek, Two Creeks, Harrison Creek, and smaller drainages at middle and lower elevations.

Elk are the dominant big game, with a resident herd distributed across the unit year-round; the bulk of the population summering on the Grand Mesa plateau (8,500–10,000 ft) before migrating to lower oakbrush and pinyon-juniper winter range in the Plateau Creek drainage as snow accumulates. Mule deer follow a similar vertical migration pattern, with resident animals in the lower agricultural and canyon areas and higher-elevation animals moving down in October and November; the deer population has declined in recent years and the best buck opportunities occur at mid-elevations (8,500–9,500 ft) in the later rifle seasons. Black bear are present and increasing, concentrated in oak and serviceberry zones during berry season. Shiras moose occupy willow-riparian habitats along Plateau Creek, Two Creeks, and Harrison Creek drainages. Mountain lion are present in the unit. Pronghorn and wild turkey also have documented populations in and around the unit. The elk rut typically begins the first week of September and runs approximately one month.