Diamond Mtn/Vernal, Utah

Diamond Mountain is a high-elevation plateau with a pronounced rim, rising abruptly from roughly 5,300 feet at Brush Creek Junction to just under 8,000 feet along the Diamond Mountain rim. The plateau surface is gently rolling with north-south ridges and draws; the northern and western edges break steeply toward the Green River canyon. The southern margin drops via rugged canyon terrain toward Dinosaur National Monument and Jones Hole canyon. The Diamond Breaks Wilderness Study Area (Daggett County UT / Moffat County CO border, Browns Park area) consists of colorful red sandstone ridges with steep draws and canyons draining toward the Green River. Elevations in the broader Diamond Mtn/Vernal unit range from approximately 5,300 feet in the lower drainages to 8,000+ feet on the upper plateau and forested ridges.

Primary vehicle access from Vernal is via the Diamond Mountain Highway (Jones Hole Road), departing east on 500 North and climbing approximately 40 miles to the plateau rim and Jones Hole National Fish Hatchery area. Brush Creek Road intersects on the plateau and runs south toward the Island Park/Rainbow Park road, which forms the southern boundary near Dinosaur National Monument. Limestone Road from US-191 north of Vernal provides a secondary corridor onto the plateau. Road conditions deteriorate significantly during wet weather and snowfall — four-wheel drive is frequently necessary. Cell coverage is poor to moderate across the unit. The BLM Vernal Field Office administers the bulk of public land on the plateau. Private ranch holdings are significant; posted no-trespassing signs are common, and the Diamond Mountain CWMU (hunt codes DB1345/EB3617) operates on private land within the Diamond Mountain boundary. Public hunters must avoid the CWMU area. Dinosaur National Monument borders the south — hunting is not permitted within monument boundaries. The Diamond Breaks WSA (Daggett Co. UT / Moffat Co. CO) requires non-motorized access.

Vegetation on the unit varies sharply by elevation and aspect. The plateau surface is dominated by Wyoming big sagebrush and native grasses on open flats. South-facing slopes and lower rim country transition to pinyon-juniper woodland. Higher elevations and north-facing slopes support aspen groves, Douglas-fir, ponderosa pine, and limber pine. Riparian corridors — particularly Jones Hole canyon and Brush Creek — support lush streamside vegetation including willow and cottonwood. The UDWR 2020 Deer Plan notes that Wyoming big sagebrush winter range is in Fair-Poor condition across portions of the broader South Slope unit due to a 2003 die-off and cheatgrass expansion; habitat restoration (pinyon-juniper reduction, reseeding) is an active management priority. The Diamond Breaks WSA (eastern edge, Colorado border) contains limber pine and ponderosa pine transitioning down to red sandstone canyon breaks toward the Green River.

Mule deer are managed under the Diamond Mountain limited entry unit (9C) targeting a 25–35 bucks per 100 does buck:doe ratio, reflecting premium trophy management. The 2024 three-year average buck:doe ratio for the broader South Slope unit was approximately 30 bucks per 100 does, within the objective range. Rocky Mountain elk are distributed across the unit's forested north-facing slopes and upper drainages; the 9C limited entry bull elk unit targets mature bulls (mean harvest age 6.0–6.5 years). The post-season combined 9BCD elk population was estimated at approximately 2,700 animals in the most recent survey against a 3,000-animal objective. Pronghorn occupy the open sagebrush flats of the broader Diamond Mtn/Bonanza area (units 9CD). Moose are the species defining the 'Diamond Mtn/Vernal' boundary name — 2 once-in-a-lifetime permits (MB6009) are issued annually in the 9BC corridor, both resulted in harvest in 2024. Black bear frequent the unit, particularly during late summer berry and mast production seasons in aspen and conifer drainages; UDWR advises bear-proof food storage. Mountain lion inhabit the canyon breaks and forested ridges. Open-range cattle graze throughout the unit seasonally. CWD has been documented in the broader South Slope deer unit.

1. The UDWR boundary name 'Diamond Mtn/Vernal' is used exclusively for the once-in-a-lifetime bull moose hunt (MB6009, units 9BC). Mule deer LE and bull elk LE boundaries are called 'Diamond Mtn' (unit 9C). Pronghorn boundary is 'Diamond Mtn/Bonanza' (units 9CD). This profile covers the Diamond Mountain/Vernal geographic area consistent with unit_code 'diamond-mtn-vernal'. 2. Elk tag_quota (132) and harvest (88, 66.7% success) reflect 2024 LE permit data from the UDWR 2024 LE/OIAL harvest report as cross-referenced against the sibling diamond-mtn profile. The draft's figures of 103 permits / 36% / 244 harvest appear to blend spike-general and antlerless data from multiple subunits and have been corrected. 3. Deer tag_quota corrected to 165 (total LE permits: 29+102+30+4=165) with 150 harvested (not 161). 4. Pronghorn data corrected to 96 permits / 91 harvested / ~95% combined (all three seasons), not 59 permits / 100% (which reflected only the ALW season). 5. Ashley National Forest reference retained but softened — BLM Vernal Field Office is the dominant federal landowner on the plateau; Ashley NF borders the upper elevations. 6. The Diamond Mountain CWMU (DB1345 for deer, EB3617 for elk) is active within unit 9C; public-land hunters must avoid it unless holding a CWMU permit. 7. CWD has been documented in the broader South Slope deer unit per UDWR field regulations.