The Whigs gained 37 seats to win 116 and a change in partisan control, while the rival Democrats lost 30, falling to 112.

The war had much stronger voter support in the West, South, and among Democrats than in the East, North, and among Whigs.

It was widely, accurately believed that war with Mexico would be won with large territorial gains.

The Wilmot Proviso was the first congressional attempt to address slavery in these projected new territories, by proposing to ban it.

The repeated failure of Congress, and later also the President and Supreme Court, over the next decade to resolve the issue of slavery in the territories was a major cause of the Civil War.

Notable freshmen included Abraham Lincoln of Illinois, elected as a Whig to his only term.

In 1845, partly motivated by the successful 1844 test of the electric telegraph between Washington and Baltimore, Congress established a uniform date for choosing Presidential electors.

Elections were held August 2, 1847, after the March 4, 1847 beginning of the term, but before the House first convened in December 1847.

Elections were held August 2, 1847, after the March 4, 1847 beginning of the term, but before the House first convened in December 1847.

Elections were held August 2, 1847, after the March 4, 1847 beginning of the term, but before the House first convened in December 1847.

Elections were held August 2, 1847, after the March 4, 1847 beginning of the term, but before the House first convened in December 1847.