To the right of the name and service date you will find a numerical ranking for each senator. Beginning with the election of 1958, Senators are listed according to commencement of first Senate term by seniority (determined by former service in order as senator, vice president, House member, cabinet secretary, governor, and then by state population). Prior to 1958, senators whose terms began on the same day are listed here alphabetically, rather than by seniority.
A Chronological Listing of U.S. Senators
