Miller Hills

Miller Hills is a 10,377-acre Inventoried Roadless Area in the Thunder Basin National Grassland of northeastern Wyoming. The area sits on the rolling, arid prairie that drains the upper Cheyenne River, in country shaped by low precipitation, hard summer winds, and short, intense storms. The named hills of Miller Hills give the area its topographic relief, while the land surface is incised by a set of ephemeral drainages — West Fork Rattlesnake Draw, Nachtman Draw, Sawmill Draw, Rattlesnake Draw, and Good Draw — that gather runoff and channel it toward Wagonhound Creek and the Meadow Creek-Cheyenne River headwaters. Surface water moves only seasonally through most of these draws, leaving streambeds dry through much of the year and concentrating moisture in the alluvial bottoms where it supports a different vegetation than the surrounding uplands.

The plant communities of Miller Hills track these moisture and soil gradients closely. The dominant cover is Northern Great Plains Mixed Grass Prairie, a long-evolved community of cool-season and warm-season bunchgrasses that occupies the rolling uplands and shoulder slopes. Where soils deepen on broader benches, Great Basin Big Sagebrush Steppe takes over, with Wyoming big sagebrush forming the matrix above a perennial grass understory. Saline and alkaline soils on flats and lower swales hold Intermountain Saltbush Flats and Intermountain Greasewood Flat, salt-tolerant dwarf-shrub communities adapted to fine-textured, chemically restrictive soils. Sandier patches support Great Plains Sand Prairie, a wind-shaped community keyed to coarse substrate. Where local relief and aspect allow tree establishment, Black Hills Ponderosa Pine Woodland and Savanna reaches the area from its main range to the north and east, holding scattered ponderosa pine on north-facing slopes and rocky exposures. A small fringe of Intermountain Mountain Sagebrush Steppe occurs at the higher edges. The draws themselves carry Great Plains Wooded Draw and Ravine and Northern Great Plains Streamside Habitat, narrow ribbons of green willow, cottonwood, and shrub canopy that stand out against the open prairie.

The ecological structure of this landscape is built on the relationship between the open mixed-grass uplands, the sagebrush and saltbush flats, and the wooded draws. The grassland matrix is the production base — forage and seed for prairie herbivores, cover for ground-nesting birds, and connected range for wide-ranging mammals. The sagebrush and saltbush flats add habitat structure and shelter on otherwise exposed country. The wooded draws function as concentrated cover and water sources, supporting species that cannot persist on the open prairie alone. The continuity among these types — the absence of fences cutting across draws or roads scraping the uplands — is what allows fire, grazing, and seasonal water to operate at the scales the system evolved with. Portions of this area fall within the potential range of several federally listed species; see the Conservation section for details.

A person walking from the uplands of Miller Hills down into Rattlesnake Draw moves through a sequence of bunchgrass and sage, then into the cooler, denser shade of the wooded draw bottom. Above, the prairie runs open to the horizon; below, the dry watercourse holds the only trees in sight.

Miller Hills lies in the Dry Fork of the Cheyenne River country of Converse County, Wyoming, in a stretch of high plains that the Lakota, Northern Cheyenne, and Arapaho moved through long before Euro-American settlement. The intertribal territory of the northern plains crossed this drainage; Oglala Lakota parties continued to travel through it after the establishment of the reservations to the east, gathering medicinal plants and hunting game on familiar ground. That continuing use ended violently in 1903. On October 31, 1903, an Oglala party from the Pine Ridge Reservation, "headed back to the reservation after a trip to search for medicinal plants," was overtaken near Lightning Creek "on the Dry Fork of the Cheyenne River about 50 miles northeast of Douglas, Wyo." [1] by a sheriff's posse out of Newcastle. "The posse continued until they found the William Brown and Charles Smith parties on the Dry Fork of the Cheyenne River north of present Bill, Wyo." [1] In the shooting that followed, seven people died, including Sheriff William Miller and the eleven-year-old Peter White Elk. Indian Agent McNichols later wrote that "the trouble at Lightning Creek, resulting in part from a 'local sentiment of race hatred, has stained a page in Wyoming's history.'" [1] "The Lightning Creek battle has been called the 'last blood-spilling fight' between whites and American Indians in Wyoming." [1]

Euro-American settlement of the surrounding plains came under federal homestead law. "In order to facilitate settlement of the Great Plains and other areas of the sparsely populated West, Congress enacted the Homestead Act of 1862 which authorized the disposition of 160 acre parcels of federal land to qualified individuals." [2] When that allotment proved too small for dryland farming, "Congress enacted the Enlarged Homestead Act in 1909, doubling to 320 acres the amount of land that could be homesteaded west of the 100th meridian" [2]. Homesteaders moved onto the Converse County grasslands, breaking sod and running stock on country whose thin soils and unreliable precipitation made farming marginal at best. The Great Depression and the Dust Bowl pushed many of these operations past the point of recovery.

Federal policy then reversed itself. "Beginning in the 1930's, the Government launched a large scale 'land utilization program'… to respond to many of the agricultural problems plaguing the country." [2] "The LUP began as a submarginal land purchase and development program" and "culminated with the passage of the Bankhead-Jones Farm Tenant Act of 1937" [2]. Funds were used to "purchase sub-marginal homesteads in 1934/5" [3]; from "1937-1953: Soil Conservation Service managed land utilization projects" [3], and in "1953: management turned over to USFS" [3]. "In 1960, the Secretary designated approximately 3.8 million acres of LUP land mostly in the Great Plains as national grasslands" [2], including the 560,166-acre Thunder Basin National Grassland in Wyoming [2]. Miller Hills is a 10,377-acre Inventoried Roadless Area within this grassland, on the Douglas Ranger District, and is protected under the 2001 Roadless Area Conservation Rule.

Vital Resources Protected

• Unfragmented Mixed-Grass Prairie: The roadless condition keeps the Northern Great Plains Mixed Grass Prairie and Great Basin Big Sagebrush Steppe — which together cover roughly 60% of Miller Hills — as a continuous landscape rather than a network of fenced and roaded fragments. Continuous prairie supports landscape-scale fire and grazing dynamics, ground-nesting bird habitat, and movement corridors for wide-ranging mammals. Across the region, this community type has been reduced by roughly half through agricultural conversion.

• Ephemeral Draw and Streamside Function: The named draws — West Fork Rattlesnake, Nachtman, Sawmill, Rattlesnake, and Good Draws — carry Great Plains Wooded Draw and Ravine and Northern Great Plains Streamside Habitat. These narrow woody ribbons concentrate water, shade, and cover in an otherwise open landscape, and channel seasonal runoff to Wagonhound Creek and the upper Cheyenne River. The roadless condition preserves the natural hydrology and intact woody canopies that make these draws function as wildlife refugia.

• Saline-Soil and Sand Prairie Plant Communities: Intermountain Saltbush Flats, Intermountain Greasewood Flat, and Great Plains Sand Prairie occupy fine-textured, chemically restrictive, or wind-shaped soils that are particularly slow to recover from disturbance. The roadless condition keeps biological soil crusts and dwarf-shrub cover intact, preserving the soil stability and the salt-tolerant plant assemblages these communities depend on.

Potential Effects of Road Construction

• Direct Habitat Conversion and Fragmentation: Road construction across mixed-grass prairie permanently converts native sod to a graded prism and a maintained right-of-way, dividing the contiguous prairie into smaller patches. Edge effects extend well beyond the road surface — altered microclimate, predator access for nest predators, and increased disturbance — degrading habitat for prairie-dependent species and disrupting fire and grazing patterns that require unbroken extent.

• Invasive Species Corridors: Construction traffic and exposed cut slopes introduce and spread invasive non-native grasses such as cheatgrass (Bromus tectorum) into Mixed-Grass Prairie and Big Sagebrush Steppe. Once established along road corridors, cheatgrass shortens fire-return intervals and converts native shrub-steppe to annual grassland — a transition that, regionally, has proven essentially irreversible without intensive, sustained intervention.

• Soil Erosion and Drainage Alteration on Arid Soils: Cut-and-fill construction across the fine-grained salt soils of Intermountain Saltbush Flats and the loose substrates of Great Plains Sand Prairie initiates water and wind erosion on terrain whose vegetation cover is naturally sparse. Roads also alter the timing and concentration of runoff into the ephemeral draws, scouring the wooded-draw bottoms and changing the hydrology that supports streamside habitat. Recovery of these arid-soil communities, once disturbed, takes decades to centuries.

Miller Hills covers 10,377 acres of arid prairie and broken draw country in the Thunder Basin National Grassland, on the Douglas Ranger District in Converse County, Wyoming. The area has no maintained trails, no designated trailheads, and no developed campgrounds recorded in the verified data. Use is dispersed: cross-country foot travel from the surrounding road network, with route choices keyed to the named drainages — West Fork Rattlesnake Draw, Nachtman Draw, Sawmill Draw, Rattlesnake Draw, and Good Draw — and to the modest topography of Miller Hills itself. Visitors should consult the most recent Thunder Basin National Grassland motor vehicle use map and Forest Service travel direction before entering, and should respect intermingled private inholdings characteristic of this district.

Hunting is the primary documented use. The Northern Great Plains Mixed Grass Prairie and Great Basin Big Sagebrush Steppe across the uplands provide pronghorn antelope range, while the wooded draws — Great Plains Wooded Draw and Ravine and Northern Great Plains Streamside Habitat — offer concentrated cover for mule deer. Stands of Black Hills Ponderosa Pine Woodland and Savanna on the higher north-facing breaks add timbered habitat at a small scale. Wyoming Game and Fish Department hunt-area boundaries, license requirements, and season dates apply. Hunters who walk in from the surrounding road network have the country to themselves; the closest motorized access ends at the boundary.

Birding is supported by the contrast between the open prairie matrix and the woody draw bottoms. The Thunder Basin National Grassland eBird hotspot at the 942 Road and Coal Bank Draw area, within 24 kilometers of Miller Hills, documents 106 species for the broader landscape, giving a baseline for what to look and listen for. Inside the area itself, expect grassland songbirds across the bunchgrass uplands, sage-obligate species in the Big Sagebrush Steppe, and a different bird community concentrated in the cottonwood and shrub canopy of the draws. Raptors hunt the open ridges. Birders should pull together their own checklist on the ground rather than relying on a fixed trail.

Photographers will find the area's strongest material along the contrast lines — the dry uplands against the green ribbons of the draws, sagebrush against sandstone exposures, and the long, low light of morning and evening across rolling prairie. Dispersed backcountry camping is possible subject to current Forest Service direction; there are no developed sites. Snow conditions in winter are variable, and high winds are a constant.

Every activity described here depends on the roadless condition. The open horizon, the working hydrology of the draws, and the dispersed character of hunting and birding all turn on the absence of new roads cutting across the prairie. Road construction would replace the present quiet, low-density use with the narrow, motorized strip a vehicle can reach, and would compress the experience of the country into the immediate vicinity of the new corridor.