Abstract Lesquerella prostratais a regional endemic of southwest Wyoming, northeast Utah, and southeast and central Idaho. It is currently known from fewer than 15 locations worldwide, 6 of which are found in the southern Overthrust Belt in Uinta and Lincoln counties, Wyoming. These populations are restricted to dry, sparsely vegetated, desert slopes of whitish or reddish limey clays and soft sandstones of the Green River, Wasatch, and Bridger formations. Wyoming populations contained 4700-11,000 individuals in less than 100 acres of occupied habitat during surveys in 1996 and 1999. Comparable data are lacking for out-of-state populations, although one Idaho populations was reported as “locally common” in 2000. Threats have traditionally been low for this species due to its rugged habitat. The recent growth of the natural gas industry in southwest Wyoming makes this species more vulnerable to surface disturbances from road and pipeline construction associated with mineral exploration, as well as from habitat loss from off-road vehicle recreation. Due to its small range and low population numbers, L. prostratashould be considered for possible designation as a BLM state sensitive species. Additional surveys are needed in Utah and Idaho before rangewide conservation recommendations can be made.