After successfully breaking the Confederate siege at Chattanooga near the end of 1863, William Tecumseh Sherman united several Union armies in the Western theater for the Atlanta Campaign, forming one of the biggest armies in American history. After detaching troops for essential garrisons and minor operations, Sherman assembled his nearly 100,000 men. In May 1864, he began his invasion of Georgia from Chattanooga, Tennessee, where his forces spanned a line roughly 500 miles wide.

Sherman set his sights on the Confederacy's last major industrial city in the West and on General Joseph E. Johnston's Army of Tennessee, which aimed to protect it. Atlanta's use to the Confederacy lay in its terminus for three major railroad lines that traveled across the South: the Georgia Railroad, Macon and Western, and the Western & Atlantic. US Lieutenant General Ulysses S. Grant knew this, sending Major General William Tecumseh Sherman's Division of the Mississippi towards Atlanta with the specific instructions, "[G]et into the country as far as you can, inflicting all the damage you can against the war revenues." The city's ability to send supplies to Lee's Army of Northern Virginia made Atlanta all the more important.

The people of Atlanta clearly identified their own role in the struggle, as the Atlanta Daily Appeal noted, "The greatest battle of the war will probably be fought in the immediate vicinity of Atlanta. Its result determines that of the pending Northern Presidential election. If we are victorious the Peace party will triumph; Lincoln's Administration is a failure, and peace and Southern independence are the immediate results."