This is a complete list of United States senators during the 2nd United States Congress listed by seniority from March 4, 1791, to March 3, 1793.
The order of service is based on the commencement of the senator's first term, with senators entering service the same day ranked alphabetically. The Senate subsequently assigned a consecutive official number to each senator, which is the second number given in the table.
During this time, there were no official parties, but senators are labeled as Pro-Administration (P), and Anti-Administration (A).