1848–49 United States House of Representatives elections

States held the 1848–49 United States House of Representatives elections between August 7, 1848 and November 11, 1849. Each state set a date for its elections to the House of Representatives before the first session of the 31st United States Congress convened on December 3, 1849. The new state of Wisconsin elected its first Representatives. Anticipating statehood, as ratified in September 1850, California held Federal elections beforehand, increasing the size of the House to 233 seats.

These elections spanned the 1848 United States presidential election and took place immediately after the U.S. victory over Mexico in the Mexican–American War. The Whigs lost their House majority as Democrats, whose support had driven the war, won a plurality. Among minor parties, the new Free Soil Party, which opposed slavery in the Western territories, won nine Northern seats, while the American or Know Nothing Party retained one.

Despite winning most of their seats at Whig expense, the Free Soil Party had coalesced in 1848 largely as a result of a Democratic Party split in New York, the most populous state. The new party thus drove an unusual Whig sweep in New York elections, temporarily masking Whig decline.

After a gold discovery in January 1848, California boomed, drawing rapid migration of new residents and creating immediate pressure for statehood. The Compromise of 1850, though largely crafted in the Senate, was also passed by the House, brokering its admission to the Union.

As no party held a majority when Congress convened, the election of a Speaker proved contentious. The Whigs were sectionally split, with Northern Whigs nominating incumbent speaker Robert C. Winthrop of Massachusetts and Southern Whigs supporting Meredith P. Gentry of Tennessee. Democrats primarily supported Howell Cobb of Georgia; 13 other Democratic hopefuls also garnered support. The small Free Soil Party supported David Wilmot of Pennsylvania, author of the Wilmot Proviso, calling attention to slave power's hold over both major parties.

After nearly three weeks of heated debate, the House suspended its majority rule for the Speaker election, enabling Cobb to be elected on the 63rd ballot by plurality.