Unit 87, Colorado

Elevation ranges from approximately 4,900 to 6,000 feet. The western portion is rolling shortgrass prairie dissected by numerous seasonal creeks. Near the Wyoming border, prominent mesas and the Chalk Bluffs rise more than 1,000 feet above the surrounding prairie, with some steep, rugged canyons and arroyo drainages cutting through the breaks. The Pawnee Buttes — the unit's most distinctive geologic landmarks — are two sandstone formations protruding from the grassland floor, with the west butte on National Grassland and the east butte on private land. Overall slope is gentle: approximately 80% of the area has a slope of 5% or less.

Primary public land is the Pawnee National Grassland (193,060 acres total), administered by the Pawnee Ranger District under the Arapaho and Roosevelt National Forests (field office: 115 2nd Ave., Ault, CO 80610; phone 970-295-6600; open by appointment Mon–Fri). The grassland's two non-contiguous parcels spread across Weld County in a checkerboard pattern with private inholdings, State Trust Lands (most leased, limiting public access), and active oil-and-gas development. Colorado State Highway 14 (the Pawnee Pioneer Trails Scenic Byway) runs east-west through the western grassland parcel near Briggsdale and provides the main paved corridor into the grassland from Fort Collins and Ault. Colorado State Highway 71 crosses the eastern grassland parcel. A network of Weld County gravel roads — including County Road 77 near Briggsdale and County Road 390 — provides access to interior grassland parcels. ATVs no wider than 50 inches are allowed on designated roads November 1 through April 9 on National Grassland. Crow Valley Recreation Area northwest of Briggsdale offers the primary developed campground. The Central Plains Experimental Range (14,000+ acres, USDA Agricultural Research Service) is closed to all hunting and is not part of Pawnee National Grassland. Hunters must use a current Pawnee National Grassland motor vehicle use map or GPS mapping (OnX, Gaia) to navigate the checkerboard. Nearest supply towns: Ault (on SH-14), Briggsdale (SH-14 interior), Grover (between the two grassland parcels), and Fort Collins (~17 miles west).

Dominant cover is shortgrass prairie consisting primarily of blue grama and buffalo grass, with mixed-grass swales containing needle-and-thread, western wheatgrass, and little bluestem on north-facing slopes and draws. Rocky Mountain juniper and chokecherry grow in arroyos and scarp woodlands around the Chalk Bluffs and canyon rims; fourwing saltbush shrub steppe occurs on clay and disturbed soils. Scattered limber pines appear on north-facing scarp faces near the Pawnee Buttes. Conservation Reserve Program (CRP) fields add patches of replanted native grasses. Irrigated alfalfa and corn fields around Ault and Grover provide seasonal green forage attracting deer and pronghorn. There is no aspen, spruce-fir, or alpine tundra; the unit is entirely plains and foothill-grassland vegetation.

Pronghorn antelope are the signature big-game species and were historically abundant enough to produce record-book bucks, though populations declined over the past 12-15 years following increased tag quotas and severe winter weather events. Pronghorn movement is largely year-round on the grassland, with some drift toward lower, more sheltered terrain during severe winter weather. Mule deer are the second primary big-game target and inhabit the grassland year-round, concentrating near creek drainages and CRP fields; bucks historically included quality animals, though most large bucks now tend to be on adjacent private land. Mule deer follow creek corridors and shift to agricultural fields in fall and winter. White-tailed deer occur along creek bottoms and irrigated agricultural areas near Ault and Grover but are far less common than mule deer. Elk are rarely observed in the unit — it lies well outside established Colorado elk range and sightings are incidental. Non-game wildlife is diverse: prairie dogs, black-tailed jackrabbits, coyotes, golden eagles, and prairie falcons are common; the Chalk Bluffs area is a documented raptor concentration and nesting site.

1. Public land percentage (26%) sourced from GoHunt unit profile; effective accessible public land is lower due to checkerboard private inholdings and leased State Trust Lands. 2. Pronghorn hunter success rate corrected to 73% (GMU 87 specific per Backfire/CPW data, year unspecified pre-2023); the draft's 69% figure was a combined GMU 87/88/89 estimate — removed. 3. CPW draw recap PDFs are password-protected; unit-specific quota and harvest numbers for 2024-2026 are unavailable. 4. Pronghorn OTC archery license sale date corrected to Aug 4, 2026 (season opens Aug 15). 5. SH-14 description corrected: runs through the western parcel near Briggsdale (not strictly 'southern edge'). 6. Elk removed from species_data: open plains unit, species absent or incidental, no hunt codes issued. 7. CPER (14,000+ acres, USDA ARS) is closed to all hunting and is distinct from Pawnee National Grassland. 8. All 2026 season dates are statewide guidelines; always verify individual hunt codes against the 2026 Big Game Brochure.