The city is located at an elevation of 4,336 feet (1,322 m) on the western flank of the Sacramento Mountains and on the eastern edge of the Tularosa Basin. It is in the Rio Grande rift and in the northernmost part of the Chihuahuan Desert. Tectonic activity is low in the Tularosa Basin. Plants native to the area are typical of the southern New Mexico foothills and include creosote bush, mesquite, saltbush, cottonwood, desert willow, and many species of cactus and yucca.
The Tularosa Basin is a closed basin, that is, no water flows out of it. Because of this and because of the geology of the region, water in the basin is hard: it has very high total dissolved solids concentrations, in excess of 3,000 mg/L. The Brackish Groundwater National Desalination Research Facility, a Bureau of Reclamation laboratory doing research and development on desalination of brackish water, is located in Alamogordo. The gypsum crystals of White Sands National Monument are formed in Lake Lucero. Water drains from the mountains carrying dissolved gypsum and collects in Lake Lucero. After the water dries, the winds pick up the gypsum crystals and distribute them over the basin
