Delaware's at-large congressional district is a congressional district that includes the entire U.S. state of Delaware. It is the nation's oldest congressional district, having existed uninterrupted since the 1st United States Congress in 1789. With 1,051,917 residents, the district has the highest population of any congressional district in the nation. Delaware has always had only one member of the United States House of Representatives, except for a single decade from 1813 to 1823, when the state had two at-large members. The two seats were filled by a statewide ballot, with the two candidates receiving the highest votes being elected. The district is represented by Democrat Sarah McBride.
Mike Castle, a Republican and former governor of Delaware, held this seat from January 1993 until his retirement in January 2011, after his unsuccessful bid for the Republican nomination to run for U.S. Senator. Even as Delaware swung heavily Democratic at the state and national level, Castle was usually reelected without serious difficulty. Since his retirement, however, the Democrats have held it with no substantive opposition.
The district is currently represented by Sarah McBride, a Democrat, who was first elected in 2024. McBride is the first openly transgender person elected to Congress.
From 1813 to 1823, Delaware elected two members of the United States House of Representatives. Both were elected statewide at-large. Four men held the second seat during that decade.