August 2, 1846 - November 2, 1847 1848 → 142 seats 6 seats 112 1 Start date 1846 | 79 seats 142 seats 116 112 37 30 | |
 | ||
Winner Robert Charles | ||
Elections to the United States House of Representatives for the 30th Congress were held at different dates in the various states, from August 2, 1846 (Missouri) to November 2, 1847 (Mississippi and Louisiana) during James K. Polk's term in office. The Whigs picked up 37 seats to win 116 seats, while the rival Democrats lost 30 and fell to 112 seats in the House. The result was a switch of partisan control of the House, with the Whigs gaining a narrow majority of just four seats. The Whigs picked up seats in New England and the South. The nativist American Party, dedicated to opposition to immigration and anti-Catholicism, lost five of its Representatives and was left with only a single seat. In addition, one Independent, Amos Tuck, was elected to New Hampshire's 1st District.
The Mexican–American War was the biggest issue of concern during this election. While the war was widely supported west of the Appalachian Mountains, many people in eastern urban regions were opposed. The extreme loyalty of the Democratic Congress—with only 14 representatives voting against the war—was a huge factor in the Whig pick-up. Growing divisions over slavery were also a contentious concern, as this ever-present issue had been brought to the forefront by Congressional rejection of the Wilmot Proviso.
Notable freshmen include future president Abraham Lincoln, elected as a Whig to his first and only term in this election.
Election summaries
The remaining multi-member at-large districts were abolished for this election, leaving all states with two or more Representatives divided into districts. In 1845, Congress had passed a law establishing a uniform date throughout the Union for choosing electors. The law did not apply to Congressional elections, but the date was gradually adopted for Congressional elections as well. In 1846, only three states (Michigan, New Jersey, and New York) used that date (November 3, 1846).
Two seats were added for the new State of Wisconsin. Wisconsin was unrepresented for most of the 1st session.