Unit 143, Nevada

The unit spans a wide elevation band from approximately 4,700 feet in Crescent Valley and Kobeh Valley basin floors to 10,133 feet at Roberts Creek Mountain, the high point of the Roberts Mountains range. Terrain is highly varied: broad, flat sagebrush valleys give way to rolling foothills, then to steep, rocky ridgelines above 8,500 feet. The Roberts Mountains extend roughly 16 miles east-west and 14 miles north-south. The geologic character reflects the Antler orogeny (Late Devonian to early Mississippian), producing carbonate ridges, thrust-faulted terrain, and broken rocky formations at upper elevations, where oceanic island arc volcanics were emplaced over Devonian to Silurian carbonates.

Unit 143 is managed almost entirely by the BLM Battle Mountain District (Battle Mountain Field Office, 50 Bastian Road, Battle Mountain, NV 89820; 775-635-4000). Public land comprises approximately 97% of the unit; private inholdings and mining operations are present but do not block public access to the surrounding range. Major highway corridors: US Highway 50 forms the southern boundary (Eureka is the closest services town); Nevada State Route 278 runs along the eastern margin through Garden Valley; the Cortez-Beowawe Road defines the northern boundary; Three Bars Road marks the western boundary. Internal access is via a network of maintained BLM gravel roads and two-track trails accessing both sides of the Roberts Mountains; high-clearance or 4WD vehicles are recommended in wet conditions. The Roberts Mountain Wilderness Study Area (15,090 acres, Eureka County) lies within the unit — motorized travel is prohibited off established roads within this WSA. No designated National Forest land is present in the unit. Eureka (US-50) provides lodging, fuel, and resupply; Battle Mountain and Austin also provide gas, food, and lodging. Roberts Creek Road and County Road 101 from Eureka are common entry routes into the range interior. Feral horse overabundance in the Roberts Mountain, Whistler Mountain, and Fish Creek HMAs (pre-2023-gather estimate of 1,161 horses in Roberts Mtn and Whistler Mtn HMAs alone — over 6x the combined AML of 110-184) is an active habitat-degrading factor; 858 horses were gathered in November 2023 but the complex remains above AML.

Vegetation follows a classic Great Basin elevational gradient. Valley floors (4,700–6,000 ft) support Wyoming big sagebrush, low sage scrub, greasewood, saltbush, and salt grass — classic pronghorn habitat. Pinyon-juniper woodland dominates the foothills and mid-slopes from roughly 6,000–7,500 feet; BLM and NDOW have conducted extensive pinyon-juniper removal and retreatment on Lone Mountain, the east Whistler Range, and multiple locations on Roberts Mountain (Pete Hansan, Henderson Creek, Vinini Creek, and Roberts Creek corridors) to restore sagebrush-steppe. Aspen pockets occur near springs and drainages, and mountain mahogany is common on upper ridges from 7,500–8,500 feet. Large single-leaf pines occupy the highest terrain. Post-fire cheatgrass encroachment and annual grass proliferation are active management concerns; over 450,000 acres across Management Area 15 have burned since 1999 with ongoing rehabilitation.

Mule deer are the primary big game species, present year-round with summer range concentrated in the upper elevations of the Roberts Mountains, Roberts Creek, Sulfur Springs, and adjacent ranges; winter range drops to the Cortez, Diamond, Whistler, and Fish Creek Ranges within the broader Management Area 14. The biologist-recommended hunting areas for unit group 141-145 note the Diamond Range (Unit 144) holds the majority of the deer; Roberts Mountain (Unit 143) has a smaller population but good hunting early in the season, with the Fish Creek Range improving late in October as deer migrate through. The November 2023 post-season aerial survey for unit group 141-145 classified 1,850 deer at 27 bucks:100 does:58 fawns — the highest sample since 2007; a March 2024 spring survey counted 2,044 deer at 41 fawns:100 adults. Pronghorn antelope occupy the open sagebrush valley floors and basin benches year-round; Antelope Valley, Lower Reese River Valley, Crescent Valley, and the benches of the Simpson Park and Cortez Mountains are known concentration areas per the 2024 NDOW status report. The unit group 141,143,151-156 antelope population has grown from roughly 100 animals in the early 1980s to several thousand; a January–February 2024 ground survey classified 1,943 antelope at 61 bucks:100 does:44 fawns. Mountain lion is present statewide with OTC tags; follows deer prey. Chukar partridge and greater sage-grouse inhabit appropriate shrub-steppe and rocky slope habitats. Feral wild horses (Roberts Mountain, Whistler Mountain, and Fish Creek HMAs) are a significant wildlife competitor for water and forage, with ongoing BLM gather efforts. Rocky Mountain elk are not established in unit 143; small numbers occur seasonally in neighboring units 144 and 145 and are actively managed via depredation hunts to prevent population establishment per the Central Nevada Elk Plan.