The 30th 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, 1847, to March 4, 1849, during the last two years of the administration of President James K. Polk. The apportionment of seats in the House of Representatives was based on the 1840 United States census. The Senate had a Democratic majority, and the House had a Whig majority. It was the only Congress in which Abraham Lincoln served.

The 29th 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, 1845, to March 4, 1847, during the first two years of James Polk's presidency. The apportionment of seats in the House of Representatives was based on the 1840 United States census. Both chambers had a Democratic majority.