Minneapolis-Saint Paul International Airport (IATA: MSP, ICAO: KMSP, FAA LID: MSP), also less commonly known as World-Chamberlain Field, is a joint civil-military public-use international airport located in Fort Snelling Unorganized Territory, Minnesota, United States. Although situated within the unorganized territory, the airport is centrally located within 10 miles (16 kilometers) of both downtown Minneapolis and downtown Saint Paul. In addition to primarily hosting commercial flights from Major American and some international airlines, the airport is also home to several United States Air Force and Minnesota Air National Guard operations. The airport is also used by a variety of air cargo operators. MSP is the busiest airport in the Upper Midwest.