Martin State Airport (IATA: MTN, ICAO: KMTN, FAA LID: MTN) is a joint civil-military public use airport located nine nautical miles (10 mi; 17 km) east of the central business district of Baltimore, in Baltimore County, Maryland, United States. The facility is located within the census-designated place of Middle River on Maryland State Highway 150 (Eastern Boulevard), near the intersection of Maryland State Highway 700 (Martin Boulevard). The Maryland Aviation Administration operates the airport on behalf of the Maryland Department of Transportation. MTN is a general aviation relief airport.