PRAIRIE MOUNTAIN. Prairie Mountain is one mile southwest of the community of Prairie Mountain in southwestern Llano County (at 30°34' N 98°52' W). At an elevation of 1,841 feet, its summit rises approximately 320 feet above nearby Ranch Road 2323. The mountain stands in an area of the Llano Basin characterized by flat to rolling terrain, locally dissected and covered with soils of sandy and clay loams. Vegetation consists primarily of open stands of live oak and mesquite.