The city of Atlanta, Georgia, in Fulton County, was an important rail and commercial center during the American Civil War. Although relatively small in population, the city became a critical point of contention during the Atlanta Campaign in 1864 when a powerful Union army approached from Union-held Tennessee. The fall of Atlanta was a critical point in the Civil War, giving the North more confidence, and (along with the victories at Mobile Bay and Winchester) leading to the re-election of President Abraham Lincoln and the eventual surrender of the Confederacy. The capture of the "Gate City of the South" was especially important for Lincoln as he was in a contentious election campaign against the Democratic opponent George B. McClellan.
The city that would become Atlanta began as the endpoint of the Western and Atlantic Railroad (aptly named Terminus) in 1837. Atlanta grew quickly with the completion of The Georgia Railway in 1845 and the Macon & Western in 1846. The city was incorporated in 1847 and extended 1 mile in all directions from the zero-mile post. In 1860, Atlanta was a relatively small city ranking 99th in the United States in size with a population of 9,554 according to the 1860 United States (U.S.) Census. However, it was the 12th-largest city in what became the Confederate States of America. A large number of machine shops, foundries and other industrial concerns were soon established in Atlanta. The population swelled to nearly 22,000 as workers arrived for these new factories and warehouses.