The Army purchased the land making up PCMS in 1983. Pronghorn, Elk, and Mule Deer are the principal large mammals found in the area. A branch of the Santa Fe Trail runs near PCMS and ancient Indian rock art and petroglyphs are common in the rocky canyons. Prior to the creation of PCMS this area was lightly populated and devoted almost entirely to ranching and livestock grazing. The Purgatoire River is the eastern boundary of the PCMS. Picketwire Canyon on the Purgatoire River. Vegetation is mostly shortgrass prairie mixed with pinyon and juniper trees. The Purgatoire River flows in a 300–400 feet deep canyon and its tributaries have cut steep arroyos into the terrain. The terrain of PCMS is flat to rolling and dotted with small, rocky hills and mesas. Annual precipitation is 12 to 16 inches (305–406 mm). Elevations on Site range from 4,300 to 5,800 feet (1,311 to 1,768 m) The Site has a semi-arid, steppe climate. The Purgatoire River, locally known as the Picketwire, is its eastern boundary. It borders on Comanche National Grassland to its north. PCMS is located northeast of Trinidad, Colorado, and is part of Las Animas County, Colorado. In 2013 the Army cancelled the planned expansion. Local residents and conservation organizations opposed the expansion. Army announced a plan to expand PCMS by purchasing additional land mostly owned by individuals and devoted to ranching.

The Piñon Canyon Maneuver Site (PCMS) is a training site for Fort Carson. The Piñon Canyon Maneuver Site (also Pinon and Pinyon) is a 235,896 acre (955 km 2) U.S.

Fort carson southern range map