Unit 40, New Mexico

Rolling high plains and rangeland bisected by the Caprock escarpment — a prominent cliff line running roughly northwest to southeast across the unit. North of the Caprock, terrain consists of prairies, arroyos, and rough canyons with mesas bearing steep sides; south of the Caprock, the landscape flattens into elevated plains sitting roughly 300–700 feet higher than the arroyos below. Elevation ranges from approximately 3,800 to 5,590 feet above sea level. The unit spans roughly 3,775 square miles.

The unit is accessed primarily via Interstate 40 (northern boundary) and US 84 (southern and western boundary), with a network of state and county roads connecting towns and ranches to primitive two-track trails. Four-wheel-drive vehicles are recommended; ATVs are useful on rough ranch roads. Public land totals approximately 10.4% of the unit — scattered BLM and state trust land parcels administered by the BLM Roswell Field Office (575-627-0272). Many parcels are landlocked by private holdings and cannot be legally reached without crossing private land. The NMDGF Open Gate Program leases access corridors across select private lands to reach otherwise inaccessible public parcels; access is free with a valid license and properties are marked with program signage. The state trust land easement (effective April 1, 2017) permits licensed hunters to access State Trust Land during valid seasons. There is no National Forest or wilderness within the unit. Camping is available at Santa Rosa Lake State Park approximately 10 miles from the unit's northwest corner. Lodging is available in Santa Rosa, Tucumcari, Fort Sumner, Clovis, and Portales.

Prairie grasses and brush, including mesquite, dominate the majority of the unit; large portions of the southern section are in cultivated cropland and improved pasture. Juniper woodlands appear on mesa tops and along the edges of the Caprock escarpment. Riparian corridors are sparse but present in arroyo bottoms. There is no substantial conifer forest — the unit lacks the pinyon-juniper highlands or ponderosa stands found in New Mexico's mountain ranges.

Pronghorn are the most abundant big-game species and are more prevalent in this unit than mule deer. Mule deer numbers are low overall, with mature bucks considered scarce on public land; deer densities are higher on private irrigated agricultural lands and around water sources. Occasional whitetail deer are reported along river and creek bottoms near the Texas border but are not a significant huntable population. No elk, black bear, cougar, turkey, bighorn sheep, oryx, or javelina are established in this unit. Pronghorn bucks enter rut from early September through mid-October.