Representative Michael N. Castle

Michael N. Castle served as a Representative from Delaware in the United States Congress from 1993 to 2011. A member of the Republican Party, Michael N. Castle contributed to the legislative process during 9 terms in office.

Michael N. Castle’s service in Congress occurred during a significant period in American history. As a member of the House of Representatives, Michael N. Castle participated in the democratic process and represented the interests of constituents.

Michael Newbold Castle (July 2, 1939 – August 14, 2025) was an American politician and lawyer who served as the U.S. representative for Delaware’s at-large congressional district from 1993 to 2011. A member of the Republican Party, he previously served as the 69th Governor of Delaware from 1985 to 1992, Lieutenant Governor from 1981 to 1985, and as a member of the Delaware General Assembly from 1967 to 1977. As of 2025, Castle was the most recent Republican to represent Delaware in the U.S. Congress and the last Republican to have been elected governor of the state. The district Castle represented includes the entire state of Delaware and is the oldest intact surviving district in the nation. He was the longest-serving U.S. Representative in the state’s history. On October 6, 2009, Castle announced his candidacy in the 2010 special election for the seat in the United States Senate held by Democrat Ted Kaufman. Kaufman, appointed by Governor Ruth Ann Minner to fill the vacancy created by Joe Biden (who resigned to become vice president of the United States), was not a candidate in the election. The election determined who would fill the balance of Biden’s term, which ended on January 3, 2015. In one of the most surprising election results of 2010, Castle lost the Republican primary to Christine O’Donnell. He would have been heavily favored in the general election against Democrat Chris Coons, who defeated O’Donnell by 17 percentage points.