By September 19, 1863, General William S. Rosecrans had assembled his widely scattered forces and established a defensive line near Chickamauga Creek. The densely wooded terrain resulted in generally desultory fighting as the opposing armies sought each other’s positions. General Braxton Bragg planned to assault both Union flanks on September 20, followed by an assault on the Union center. A blunder by Union forces resulted in a gap in the Union center only minutes before General James Longstreet attacked. The Union right flank crumpled, but the defense of Snodgrass Hill by George H. Thomas—the “Rock of Chickamauga”—saved the Union army from annihilation. Having suffered 16,000 casualties, the Union army retreated into Chattanooga. There a severely weakened Confederate army that had sustained nearly 18,500 casualties besieged it.

By September 19, 1863, General William S. Rosecrans had assembled his widely scattered forces and established a defensive line near Chickamauga Creek. The densely wooded terrain resulted in generally desultory fighting as the opposing armies sought each other’s positions. General Braxton Bragg planned to assault both Union flanks on September 20, followed by an assault on the Union center. A blunder by Union forces resulted in a gap in the Union center only minutes before General James Longstreet attacked. The Union right flank crumpled, but the defense of Snodgrass Hill by George H. Thomas—the “Rock of Chickamauga”—saved the Union army from annihilation. Having suffered 16,000 casualties, the Union army retreated into Chattanooga. There a severely weakened Confederate army that had sustained nearly 18,500 casualties besieged it.

Chickamauga battlefield. (National Archives)

The Confederate victory restored Southern morale after the twin defeats of Gettysburg and Vicksburg in early July. Union general William T. Sherman replaced Rosecrans and broke the siege with the victory at Chattanooga (November 23–25, 1863).