George McClellan (December 3, 1826-October 29, 1885) A major general for the Union Army during the Civil War. McClellan organized the Army of the Potomac and served as the general-in-chief of the Union Army from November 1861 to March 1862 when he was relieved of command by President Lincoln. McClellan was the Democratic Presidential candidate in the 1864 election, losing to the incumbent Republican, Abraham Lincoln. After the Civil War, he served as the 24th Governor of New Jersey from 1878 to 1881.