Belfast Municipal Airport (ICAO: KBST, FAA LID: BST) is a public use airport in Waldo County, Maine, United States. It is owned by the City of Belfast and is located one nautical mile (1.85 km) southwest of its central business district. Although most U.S. airports use the same three-letter location identifier for the FAA and IATA, this airport is assigned BST by the FAA but has no designation from the IATA (which assigned BST to Bost Airport in Lashkar Gah, Afghanistan).