James K. Polk

James Knox Polk was the 11th president of the United States, serving from 1845 to 1849. He previously was Speaker of the House of Representatives (1835–1839) and Governor of Tennessee (1839–1841). A protégé of Andrew Jackson, he was a member of the Democratic Party and an advocate of Jacksonian democracy. Polk is chiefly known for extending the territory of the United States through the Mexican–American War; during his presidency, the United States expanded significantly with the annexation of the Republic of Texas, the Oregon Territory, and the Mexican Cession following the American victory in the Mexican–American War.