Grant begins his advance into Virginia while Sherman, a red-haired man who will gain a lasting reputation as a major architect of modern warfare, leaves Chattanooga with one hundred thousand men to begin his march through Georgia on May 5-7.

Sherman's force is composed of three subordinate armies: the Army of the Tennessee (Grant's and later Sherman's army of 1862–63) under Major General James B. McPherson; the Army of the Cumberland under Major General George H. Thomas; and the relatively small Army of the Ohio (composed of only the XXIII Corps) under Major General John M. Schofield.

Their principal opponent is the Confederate Army of Tennessee, commanded by Gen. Joseph E. Johnston, who had replaced the unpopular Braxton Bragg after his defeat in Chattanooga in November 1863.

The fifty thousand-man army consists of the infantry corps of Lieutenant Generals William J. Hardee, John Bell Hood, and Leonidas Polk, and a cavalry corps under Major General Joseph Wheeler.