Caleb Rodney Layton was an American physician and politician, from Georgetown, in Sussex County, Delaware. He was a member of the Republican Party, who served two terms as U. S. Representative from Delaware.

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. It is also the most populous 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 and 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.