Union general in the American Civil War, b. Southampton co., Va. He served in the Seminole War and in the Mexican War. Later he taught at West Point and served in Texas. As a brigadier general of volunteers, he was sent to Kentucky, where he defeated the Confederates at Mill Springs (Jan., 1862). Thomas served under General Buell at Shiloh, Corinth, and Perryville. In the Chattanooga campaign, his stand on Sept. 20, 1863, which saved the Union army from complete rout, won for him the sobriquet Rock of Chickamauga. Appointed brigadier general in the regular army, he succeeded General Rosecrans in command of the Army of the Cumberland (Oct., 1863) and served under Ulysses S. Grant around Chattanooga and under General Sherman in the Atlanta campaign. With the fall of Atlanta (Sept., 1864), Grant ordered Thomas to pursue the army of General Hood into Tennessee. Although accused by Grant of moving too slowly, and threatened with the loss of his command, Thomas waited and finally defeated Hood at Nashville (Dec., 1864).