Washington (CNN) - Sen. Robert Byrd will become the longest-serving member of Congress Wednesday, having logged a staggering 20,774 days representing his home state of West Virginia in either the U.S. House or Senate.
Most of Byrd's tenure in federal office has been in the U.S. Senate, where he will have served 18,583 days, from January 3, 1959, through Wednesday. He became that body's longest-serving member in June 2006, surpassing the record previously held by the late Sen. Strom Thurmond of South Carolina.
The West Virginia Democrat also served a total of 2,191 days, from January 3, 1953, to January 3, 1959, in the House of Representatives
The late Carl Hayden, D-Arizona, held the previous record for longest total congressional service. Hayden served in the House and the Senate for a total 20,773 days, from February 12, 1912, to January 3, 1969.