Unit 231, Colorado

Elevation ranges from approximately 6,300 feet in the lower sage and oakbrush valleys to roughly 12,000 feet on the Flat Top peaks. The western half is defined by the Flat Top Mountains — a broad volcanic plateau with abrupt cliffs at the plateau rim — running north to south within the national forests. Between the valleys and the plateau, rolling ridges and creek drainages carry dense conifer and aspen. The unit is bounded on the east by CO-131, and the Flat Tops Trail Scenic Byway (County Road 8) runs 82 miles east-west from Yampa to Meeker through the heart of the unit. The Flat Tops plateau averages roughly 10,000 feet with volcanic cliffs on its margins.

Primary east-side access is CO-131 through Yampa (approximately 27 miles south of Steamboat Springs). The Flat Tops Trail Scenic Byway (County Road 8, 82 miles Yampa to Meeker) is the main spine road through the unit — roughly half well-maintained gravel (Yampa side) and half dirt — passable by 2WD passenger vehicles in summer but not plowed on the Yampa side in winter; open approximately June through October. Key Forest Service roads off the byway include FS Road 900 (Bear Lake Campground area, ~11 miles from Yampa) and FS Road 940 (Chapman Reservoir Campground via Dunckley Pass). Multiple wilderness trailheads provide entry into the Flat Tops Wilderness including Mandall, Smith Lake, Stillwater, Sheriff Reservoir, Baldy, East Fork, and Transfer. The Yampa Ranger District (300 Roselawn Avenue, Yampa, CO; 970-638-4516) manages the Routt NF portion; the Blanco Ranger District manages the White River NF portion. Private land is concentrated in the northern lowlands and along the eastern edge near CO-131. Wilderness regulations apply throughout the Flat Tops: no motorized vehicles, group size limited to 12 people plus livestock combined, and certified weed-free forage required for stock.

Lower elevations support sagebrush, native grassland, and scattered ponderosa pine with oakbrush thickets — prime pronghorn and mule deer winter range. Mid-elevations transition through mixed-conifer forest, oakbrush, and extensive aspen groves. The high country (10,000 ft+) is dominated by spruce-fir forest, subalpine meadows with grasses and wildflowers, and rocky alpine tundra above timberline. Riparian corridors follow Bear River and numerous tributary drainages. The Flat Tops Wilderness (second-largest in Colorado, 235,000+ acres) occupies the southwestern portion of the unit.

The White River elk herd (E-6) — the largest migratory elk herd in the world, historically near 40,000 animals — is the anchor species, with a CPW management objective of 32,000–39,000. The herd was significantly set back by the severe 2022–23 winter (worst in 70 years, with some areas seeing 50% population reductions; estimated 30,300 animals in 2023), but had recovered to within the management objective range by 2025–26, with over 18,500 elk observed in classification flights and strong spike-bull ratios indicating excellent calf recruitment. Elk summer on the Flat Tops plateau and high alpine parks, then migrate down to lower sagebrush and oakbrush winter range by November. Mule deer share the unit and follow similar elevation migrations. Pronghorn occupy the lower sagebrush flats, primarily the northern and western portions. Shiras moose are present, particularly in riparian willow and subalpine meadow areas shared with GMUs 25 and 26. Black bears range throughout the unit following berry crops and aspen groves in late summer and fall. Mountain lions are resident year-round. Wild turkey are present in lower-elevation oakbrush and ponderosa zones. Domestic sheep grazing operations are active within portions of the unit, which can affect local elk distribution.

1. Public land percentage (64%) sourced from GoHunt; official CPW/BLM acreage breakdown not separately verified. 2. Yampa is approximately 27 miles south of Steamboat Springs per USFS (draft said ~40 miles — corrected). 3. The byway road surface is approximately half well-maintained gravel (Yampa side) and half dirt — not paved (corrected from draft). 4. The unit spans both Routt National Forest (dominant, eastern/central) and White River National Forest (western portion); draft reference to Routt NF only was incomplete. 5. White River E-6 herd is accurately described as the largest migratory elk herd in the world; management objective 32,000–39,000 confirmed; historical peak ~40,000 supported by multiple sources. 6. 2nd and 3rd rifle OTC antlered elk for 2026 confirmed. 7. New pronghorn muzzleloader hunt for GMUs 15/26/231 confirmed for 2026. 8. Mountain lion combined-group harvest limit was not cleanly extractable; estimate of 75–90 is provisional. 9. Hunter success rates and 2025–26 harvest numbers not publicly available at time of research.