The 21st United States Congress was a meeting of the legislative branch of the United States federal government, consisting of the United States Senate and the United States House of Representatives. It met in Washington, D.C., from March 4, 1829, to March 4, 1831, during the first two years of Andrew Jackson's presidency. The apportionment of seats in the House of Representatives was based on the 1820 United States census. Both chambers had a Jacksonian majority.

The 20th United States Congress was a meeting of the legislative branch of the United States federal government, consisting of the United States Senate and the United States House of Representatives. It met in Washington, D.C. from March 4, 1827, to March 4, 1829, during the third and fourth years of John Quincy Adams's presidency. The apportionment of seats in the House of Representatives was based on the 1820 United States census. Both chambers had a Jacksonian majority.