Michael Newbold "Mike" Castle (born July 2, 1939) is an American politician who was Governor of Delaware from 1985 to 1992 and the U.S. Representative for from 1993 until 2011. He is a member of the Republican Party.
The district, which is the oldest in the nation, incorporates the entire state of Delaware. He was the longest-serving U.S. Representative in the state's history. Prior to his election to Congress, Castle served as a member of the Delaware General Assembly, first in the State House of Representatives (1966–1967) and then in the State Senate (1968–1976). He was the 20th Lieutenant Governor of Delaware from 1981 to 1985, and the 69th Governor of Delaware from 1985 to 1992.