POMPEY MOUNTAIN. Pompey Mountain is in northwestern Mills County (at 31°37' N, 98°38' W) six miles northwest of Mullin and just north of U.S. Highway 84. Before 1887 the nearby community of Pompey established what became the Pompey Mountain school district. For eight months in 1893 the town had a post office as well. The mountain rises at the foot of Pompey Creek to an elevation of about 1,750 feet above sea level. The surrounding area is characterized by steep slopes and benches, surfaced by shallow sandy soils that support juniper, live oak, mesquite, and various grasses.