On Wednesday, September 9, 1863 Braxton Bragg’s Confederate Army of Tennessee abandoned Chattanooga and withdrew southward into Georgia. Federal troops under General William Rosecrans immediately entered the city, while other units marched southward against Bragg.
Jefferson Davis in Richmond earlier in the month had decided to send Longstreet’s corps from Robert E. Lee’s army to assist Bragg. Longstreet was in transit when Bragg abandoned Chattanooga; the fall of the Cumberland Gap to Federal forces meant that Longstreet’s corps would have to travel by rail from Virginia through North Carolina to Atlanta, Georgia to get to the beleaguered Bragg.
It would take ten days before Longstreet could arrive; only then could the Confederates effectively attack Rosecrans and attempt to win back the initiative from Rosecrans’ advancing, Army of the Cumberland.