The 1856 American National Convention was held in National Hall in Philadelphia, Pennsylvania, on February 22 to 25, 1856. The American Party, formerly the Native American Party, was the vehicle of the Know Nothing movement. The convention resulted in the nomination of former President Millard Fillmore from New York for president and former Ambassador Andrew Jackson Donelson from Tennessee for vice president.

The 1856 United States presidential election was the 18th quadrennial presidential election, held on Tuesday, November 4, 1856. In a three-way election, Democrat James Buchanan defeated Republican nominee John C. Frémont and Know Nothing nominee Millard Fillmore. The main issue was the expansion of slavery as facilitated by the Kansas–Nebraska Act of 1854. Buchanan defeated President Franklin Pierce at the 1856 Democratic National Convention for the nomination. Pierce had become widely unpopular in the North because of his support for the pro-slavery faction in the ongoing civil war in territorial Kansas, and Buchanan, a former Secretary of State, had avoided the divisive debates over the Kansas–Nebraska Act by being in Europe as the Ambassador to the United Kingdom.