Truax Field Air National Guard Base (IATA: MSN, ICAO: KMSN, FAA LID: MSN), also known as Truax Field, is a military facility located at Dane County Regional Airport. It is located five miles (8 km) northeast of the center of Madison, a city in Dane County, Wisconsin, United States. Truax Field was named in honor of Wisconsin native Lieutenant Thomas L. Truax, who was killed in a P-40 training accident in November 1941. The airport is home to both the Wisconsin Army National Guard and the Wisconsin Air National Guard.