REAGAN CANYON. Reagan Canyon rises a mile northeast of Cupola Mountain in eastern Brewster County (at 29°40' N, 102°50' W) and extends northeast for fourteen miles to its mouth on the Rio Grande, a mile northeast of the boundary of the Black Gap Wildlife Management Area and ten miles east of Black Mountain (at 29°44' N, 102°41' W). An intermittent stream known as Reagan Creek runs through Reagan Canyon, running dry about two-thirds of a mile short of the canyon mouth. The terrain along the canyon is flat, with local shallow depressions in its upper reaches and deep and dense dissection in its lower. Soils are initially clay and sandy loams, changing to shallow, stony, clay loams at about the point that the creek runs dry. Water-tolerant hardwoods, conifers, and grasses grow near the beginning of the canyon, and in its middle and lower reaches grow oak, juniper, mesquite, chaparral, cacti, and grasses.