Presidency of James Buchanan
James Buchanan's tenure as the 15th president of the United States began on March 4, 1857, and ended on March 4, 1861. Buchanan, a Democrat from Pennsylvania, took office after defeating the Republican candidate, John C. Frémont, and the Know Nothing candidate, former President Millard Fillmore, in the 1856 presidential election.
Source: Wikipedia — Presidency of James Buchanan (CC BY-SA 4.0)