Unit 52, New Mexico

Elevation ranges from approximately 8,525 ft on the high-plains grassland and sagebrush flats to 10,912 ft at the summit of San Antonio Mountain, a free-standing dacite dome (Pliocene, ~3.36–2.9 Ma) and the highest peak in the Taos Plateau volcanic field. Much of the unit is a rolling high-elevation tableland broken by canyon drainages. The Cruces Basin Wilderness (18,867 acres) encompasses three creek basins — Cruces, Beaver, and Diablo-Escondido — that drain northward to the Rio de los Pinos. Terrain is moderately rugged; the wilderness lacks maintained trails and is considered the least visited on the Carson but not technically severe.

The unit is approximately 92% public land: USFS (Carson National Forest, Tres Piedras Ranger District), BLM, and State Trust Land, with only ~8% private. The primary highway corridor is US 285, which runs north-south through the unit connecting Tres Piedras to the Colorado border and bisects the open sagebrush flats at the base of San Antonio Mountain. San Antonio Mountain summit access is via Forest Road 418 (radio/TV tower access road; high-clearance vehicle recommended). Cruces Basin Wilderness access requires driving ~11 miles north of Tres Piedras on US 285 to Forest Road 87, then approximately 21 miles of maintained dirt road to Forest Road 572, and 2 additional miles to the Cruces Basin trailhead. FR 87 is passable to most vehicles when dry but can become impassable for days after heavy rain; FR 572's final 2 miles require high clearance. Roads are unplowed in winter. No motorized vehicles are permitted inside the Cruces Basin Wilderness. State Trust Land parcels require a Habitat Management and Access Validation (HMAV) permit.

Vegetation transitions from open sagebrush-grassland flats at lower elevations to pinyon-juniper and ponderosa pine on the middle slopes, then Gambel oak, quaking aspen, Douglas-fir, and Engelmann spruce-fir approaching the summit. High-elevation meadows and parks interspersed throughout the Cruces Basin provide elk forage. Riparian corridors along Cruces, Beaver, and Diablo-Escondido creeks support deciduous shrubs and willows. A significant 1979 forest fire reshaped much of the Cruces Basin, clearing old-growth timber and creating productive forage openings.

Elk are the dominant big game species; San Antonio Mountain hosts one of the largest winter elk concentrations in New Mexico, estimated at approximately 7,000 animals. The Chama-San Antonio herd unit (encompassing GMUs 4, 5B, 50, 51, and 52) is reported at 25,300–29,000 elk total, though this figure could not be independently confirmed from NMDGF sources consulted. Mule deer inhabit the unit's forests and shrubby parks. Pronghorn range across the open sagebrush-grassland flats, particularly at lower elevations near the base of San Antonio Mountain along US 285. Rocky Mountain bighorn sheep have confirmed draw hunts in Units 50 and 52 (Aug 16–18 and 23–25, 2025). Black bear are present throughout the forested portions. Cougar inhabit the unit year-round. Merriam's turkey occupy ponderosa pine and mixed-conifer zones. Elk migrate from higher elevations in adjacent Colorado units into GMU 52 as fall snowpack builds.