The Confederate Army of Tennessee under Braxton Bragg defeated the Union Army of the Cumberland under William Rosecrans at Chickamauga in northern Georgia on 19-20 September 18632. A mistaken order opened a gap in the Union line just as James Longstreet's assault struck it, routing the Union right; but Major General George H. Thomas held the left on Snodgrass Hill, earning the name the Rock of Chickamauga and saving the army, which fell back into Chattanooga. It was the bloodiest battle of the war's Western Theater.
In the autumn of 1863 the two western armies collided in the tangled woods along Chickamauga Creek, just over the Georgia line from Chattanooga. It was some of the most confused and savage fighting of the American Civil War, a Confederate victory bought at a fearful price, and it is remembered above all for one general who refused to run.
Part of The greatest battles of the Civil War · Before: The Second Battle of Fort Wagner · Next: The Battle of the Wilderness
The road to Chickamauga
In the late summer of 1863 the Union Army of the Cumberland under William Rosecrans maneuvered the Confederates out of Chattanooga, the vital rail gateway3 to the Deep South, and pushed on into the mountains of northern Georgia with its corps dangerously spread apart. Braxton Bragg, heavily reinforced, including much of James Longstreet's veteran corps, sent by rail from Robert E. Lee's army in Virginia, turned to fight along Chickamauga Creek, whose name is often translated as the river of death.
Two days in the woods
The battle opened on 19 September in dense, trackless woodland where neither side could see far. It became a soldiers' fight, brigade slamming into brigade among the trees, attacks flaring up and down the line and dying away without decision. By nightfall both armies had fed in most of their men and dug in for the morning, and the killing had already been immense.
The gap in the line
On the morning of 20 September Bragg attacked in force. In the confusion a Union officer reported a gap in the line that was not there; Rosecrans ordered a division to shift and close it4, and in doing so opened a real gap in his front. At that very moment Longstreet's massed columns struck exactly that point. The Union right was torn apart and swept from the field, carrying a third of the army5, and Rosecrans himself, back toward Chattanooga in a rout.
The Rock of Chickamauga
The battle might have become a catastrophe, but on the Union left George H. Thomas refused to break. He gathered shattered and stray units on Snodgrass Hill5 and Horseshoe Ridge and held them there against attack after attack through the afternoon and into dusk, buying the time the rest of the army needed to escape. For that stand he was ever after known as the Rock of Chickamauga.
The cost and the aftermath
Chickamauga cost around 34,000 men killed, wounded and missing on the two sides together, the second bloodiest battle of the Civil War after Gettysburg1 and by far the worst in the Western Theater. Yet Bragg had won a field, not a campaign. The Union army fell back into Chattanooga, where the Confederates besieged it, until Ulysses S. Grant arrived, reopened the supply line and broke the siege that November, turning the tide in the West for good.