Clark Air Base is a Philippine Air Force base in Luzon, located 3 miles (4.8 km) west of Angeles City, and about 40 miles (64 km) northwest of Metro Manila. Clark Air Base was previously a United States military facility, operated by the U.S. Air Force under the aegis of Pacific Air Forces (PACAF) and their predecessor organizations from 1903 to 1991. The base covered 14.3 square miles (37 km2) with a military reservation extending north that covered another 230 square miles (600 km2).