The Thirtieth 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 Sixth Census of the United States in 1840. The Senate had a Democratic majority, and the House had a Whig majority. It was the only Congress in which Abraham Lincoln served.