The Battle of Kennesaw Mountain was fought on June 27, 1864, during the Atlanta Campaign of the American Civil War. It was the most significant frontal assault launched by Union Maj. Gen. William T. Sherman against the Confederate Army of Tennessee under Gen. Joseph E. Johnston, ending in a tactical defeat for the Union forces. Strategically, however, the battle failed to deliver the result that the Confederacy desperately needed—namely a halt to Sherman's advance on Atlanta.

Sherman's 1864 campaign against Atlanta, Georgia, was initially characterized by a series of flanking maneuvers against Johnston, each of which compelled the Confederate army to withdraw from heavily fortified positions with minimal casualties on either side. After two months and 70 miles (110 km) of such maneuvering, Sherman's path was blocked by imposing fortifications on Kennesaw Mountain, near Marietta, Georgia, and the Union general chose to change his tactics and ordered a large-scale frontal assault on June 27. Maj. Gen. James B. McPherson feinted against the northern end of Kennesaw Mountain, while his corps under Maj. Gen. John A. Logan assaulted Pigeon Hill on its southwest corner. At the same time, Maj. Gen. George H. Thomas launched strong attacks against Cheatham Hill at the center of the Confederate line. Both attacks were repulsed with heavy losses, but a demonstration by Maj. Gen. John M. Schofield achieved a strategic success by threatening the Confederate army's left flank, prompting yet another Confederate withdrawal toward Atlanta and the removal of General Johnston from command of the army.