GMU 37 GMU 37 — Summit/Grand Co.
OTC bull elk in the Williams Fork and Ptarmigan Peak country north of Silverthorne, high public land between Summit and Grand counties
Central Colorado — Williams Fork Mountains and Green Mountain Reservoir · Last reviewed 2026-07-12
Area
529
sq mi
Public land
65%
approx.
Elevation
7,700–12,800
feet
Motorized
moderate
access
Overview
GMU 37 straddles the Summit–Grand county line north of Silverthorne, running from the Blue River and Green Mountain Reservoir east over the Williams Fork Mountains to the Ptarmigan Peak Wilderness and Ute Peak. Arapaho and White River National Forest cover much of the high country, giving solid public access by central-Colorado standards, while private ranch and subdivision land pinches the valley bottoms along the Blue River and Colorado River corridors. Elk are the marquee draw with an over-the-counter bull component, and mule deer post the unit's largest deer harvest through the oakbrush and aspen benches. A thin pronghorn presence exists on the sage flats near the river valleys but is a marginal, low-success opportunity.
Terrain
Sage and river-bottom valleys around Green Mountain Reservoir and the Blue River rising east through timbered slopes to the alpine crest of the Williams Fork Mountains, Ute Peak and the Ptarmigan Peak Wilderness.
Cover: Sagebrush, serviceberry and Gambel oak on the lower benches, stepping up through aspen groves into lodgepole and spruce-fir conifer, with alpine tundra and willow basins on the highest ridges.
Landmarks: Williams Fork Mountains · Ptarmigan Peak Wilderness · Ute Peak · Green Mountain Reservoir · Blue River · Ptarmigan Pass
Access
The high timber and alpine east of Green Mountain Reservoir is largely national forest, including the Ptarmigan Peak Wilderness, so the backcountry hunts well. Private ranchland and subdivisions concentrate along the Blue River, the Colorado River corridor near Kremmling, and the reservoir shoreline — know exactly where the forest boundary lies before working the valley. Colorado State Trust Lands here are generally NOT open to hunting unless enrolled in CPW's Public Access Program; do not treat them as open. The wilderness is foot or horseback only.
Managers: USFS Arapaho National Forest, USFS White River National Forest, USFS Ptarmigan Peak Wilderness, BLM, private ranch
Access points: Ute Pass Road (CR 3) over the Williams Fork Mountains · Green Mountain Reservoir and Heeney area forest roads · Ptarmigan Peak Wilderness trailheads above Silverthorne · Blue River / CO Highway 9 corridor north of Silverthorne
Species notes
Rocky Mountain Elk
common opportunityThe headline species — a resident and migratory herd across the Williams Fork timber with an over-the-counter bull season (archery plus 2nd and 3rd rifle), producing the unit's largest big-game harvest. Success is modest and pressure is real on the accessible ground; better bulls hold back in the Ptarmigan Peak Wilderness and remote dark timber.
- →Hunt the timber-to-aspen and aspen-to-sage transitions at first and last light
- →Backpack or ride into the Ptarmigan Peak Wilderness away from road-hunted OTC pressure
- →Glass high parks and dark-timber benches on the Williams Fork slopes
- →Set up on migration lines toward the Blue River valley when early snow pushes elk down
Mule Deer
common qualityFully limited-draw deer that post the unit's biggest deer harvest, scattered through the oakbrush, serviceberry and aspen edges on the lower and mid-elevation benches.
- →Glass oakbrush and serviceberry pockets mornings and evenings
- →Work the aspen-to-sage transition below the heavy conifer
- →Hunt accessible forest edges where deer feed at dawn
Pronghorn
limited lowA thin band of pronghorn use the sage flats and open benches near the river valleys, but numbers and success are marginal — a hard-to-draw, low-odds opportunity rather than a destination.
- →Glass the open sage benches near the Blue and Colorado River valleys
- →Focus on the lower, flatter ground away from timber
- →Expect long spot-and-stalk work on scattered animals
Black Bear
common opportunityBlack bear work the oakbrush-and-aspen mosaic, keying on serviceberry, chokecherry and berry crops through late summer and early fall.
- →Glass oakbrush and berry-laden hillsides in the September window
- →Concentrate on timber-brush edges and old burns
- →Watch productive mast and berry pockets at dawn and dusk
Moose
limited qualityMoose from the central Colorado herds use the willow bottoms and beaver-pond complexes of the Blue River drainage and high alpine basins; highly limited-draw only, but genuine trophy quality when a tag comes through.
- →Glass willow flats and beaver ponds along the Blue River tributaries mornings and evenings
- →Check spruce-willow riparian edges in the high basins
- →Move slowly and glass — moose sit tight in the willows
Pro tips
- →Walk or ride past the road hunters into the Ptarmigan Peak Wilderness and back timber where mature bulls hold
- →Ride out early storms — fresh snow drops elk into the aspen and oakbrush where they're huntable
- →Nail down the forest boundary along the Blue River and reservoir — private and subdivision ground pinches valley access
- →Treat pronghorn as a low-odds side opportunity, not a reason to draw here
- →Be ready for real elevation and weather on the Williams Fork crest
Watch out for
- !OTC rifle pressure on road-accessible national forest ground
- !Private ranch and subdivision inholdings along the Blue River, Colorado River and reservoir shoreline
- !State Trust Lands are closed unless enrolled in CPW's Public Access Program
- !Early-season snow can close high forest roads
- !Steep, remote wilderness terrain — plan retrieval and weather carefully
Logistics
Silverthorne and Dillon offer full services — lodging, fuel, gear and processing — 15-30 minutes south of the core country, with Kremmling closer to the north end. Ute Pass Road and the reservoir-area forest roads open the unit, but high roads turn greasy and snow-close with early storms. Expect company on accessible OTC ground during rifle seasons; solitude means a hike or horseback ride into the Ptarmigan Peak Wilderness.
Nearest towns: Silverthorne, Dillon, Kremmling, Heeney
Seasons & regulations
This page carries no season dates or regulations. Get current rules from the official Colorado sources:
Research sources: GOHUNT — Colorado Unit 37 Profile · HuntScore — GMU 37 Elk (Summit & Grand Counties) · CPW — Over-the-Counter (OTC) Licenses
FAQ
- How big is GMU 37 in Colorado?
- GMU 37 (GMU 37 — Summit/Grand Co.) covers about 529 square miles, ranging from roughly 7,700 to 12,800 feet in elevation. Area is computed from the unit boundary polygon.
- How much public land is in GMU 37?
- Approximately 65% of the unit is public land. Primary managers: USFS Arapaho National Forest, USFS White River National Forest, USFS Ptarmigan Peak Wilderness, BLM, private ranch. Always verify ownership boundaries on the ground.
- What species does the catalog list for GMU 37?
- Rocky Mountain Elk, Mule Deer, Pronghorn, Black Bear, Moose. For seasons, tags, and regulations, use the official Colorado agency resources linked on this page — this page carries no regulatory information.
Put GMU 37 on your map.
Boundary lines, public/private ownership, topo, and offline maps for this unit — in Baseline Maps, free for 14 days.