By late August, the Union army had been within three miles of Atlanta for more than a month. Confederate lines were stretched for 15 miles to protect the city. At this point, General Sherman decided it was time for action. He had only a weeks’ supply of grain for his animals and three weeks’ supply of rations for his men.
On August 31, Sherman abandoned his siege of Atlanta and launched an attack to force the Confederate army either to attack or retreat. Sherman ordered his supply wagons north of the Chattahoochee River and guarded by the XX Corps. He then moved is army west of Jonesboro cutting the Confederate railroad into Atlanta.
The loss of the railroad forced the Confederate army to evacuate Atlanta on September 1. The following morning, the Union army’s XX Corps occupied the city. General Sherman learned of the capture on September 3.
The capture of Atlanta ended Sherman’s Atlanta campaign. Sherman reported the capture in a wire to Washington, D.C. on September 3 - “So Atlanta is ours and fairly won. I shall not push much farther on this raid, but in a day or so will march to Atlanta and give my men some rest. Since May 5, we have been in one constant battle or skirmish, and need rest.”
Sherman began the Atlanta campaign with 110,000 men. His armies suffered about 37,000 casualties. The Confederate strength was about 70,000. Their losses were about 10,000 under General Johnston and about 20,000 under Hood.
During much of the siege of Atlanta the 61st OVI, including Robert Patterson, operated around the Chattahoochee River bridge. When Atlanta fell, they moved into a camp on the east side of the city. They would remain there until November 15 when it started with General Sherman’s army on its “march to the sea.”
The fall of Atlanta left little doubt that the Confederacy would be defeated in the Civil War. It was also instrumental in President Abraham Lincoln’s re-election in November 1864.