It met in Washington, DC from March 4, 1901, to March 4, 1903, during the final six months of William McKinley's presidency, and the first year and a half of the first administration of his successor, Theodore Roosevelt.

The apportionment of seats in the House of Representatives was based on the 1890 United States census.

At this time, Senators were elected by the state legislatures every two years, with one-third beginning new six-year terms with each Congress.

The Senate class numbers, which indicate the cycle of their election, precede the names in the list below.

Note:Delaware's Class 1 Senate seat remained vacant for entire Congress due to the legislature's failure to elect.