Kilbourne Hole is a maar volcanic crater, located 30 miles (48 km) west of the Franklin Mountains of El Paso, Texas, in the Potrillo volcanic field of Doña Ana County, New Mexico. Another maar, Hunt's Hole, lies just two miles south of Kilbourne Hole. Kilbourne Hole is notable for the large number of mantle xenoliths, solid fragments of mantle rock, that were carried to the surface by the eruption. Estimates of the age of the crater vary from about 24,000 to about 80,000 years.