Duluth International Airport is a city-owned public-use joint civil-military airport located five nautical miles (9 km) northwest of the central business district of Duluth, a city in Saint Louis County, Minnesota, United States. It serves the Twin Ports area, including Superior, Wisconsin. Mostly used for general aviation but also served by three airlines, it is Minnesota's third-busiest airport, behind Minneapolis–St. Paul International Airport (MSP) and Rochester International Airport.