Union Major-General William Tecumseh Sherman's telegraph--"Atlanta is ours, and fairly won"--had a huge impact on the course of the Civil War. The culmination of a four-month campaign in the Western Theater, it propelled Abraham Lincoln to reelection.
Atlanta marked the beginning of the final Confederate struggle for survival. Union forces under Sherman lined up against Joseph E. Johnston's Army of Tennessee. The superior Union numbers forced the Confederates into a series of delaying actions from entrenched positions. When John Bell Hood replaced Johnston, the Confederates launched increasingly attacking campaigns but were finally forced to give up the city as the Union troops smashed their supply lines, denying the Confederacy its principal granary and manufacturing districts.
Sherman was left to embark on his famous March to the Sea.