In August 1863, the Army of the Cumberland, under the Union General William Rosecrans, was poised to take the important Confederate railroad center of Chattanooga TN, which was defended by the Army of Tennessee under the Confederate General Braxton Bragg. In a deft move, Rosecrans swung his army through the Tennessee mountains and cut off the city’s supply lines, forcing Bragg to abandon it. Bragg made immediate plans to take it back by seizing the Union supply route at Lafayette Road.
Bragg hoped to spring a carefully laid trap. His 70,000 troops outnumbered the Federals by around 10,000—one of the few times during the war when the South had a numerical advantage. He had sent a number of spies to the Union lines to be intentionally captured and pass on the false information that the Confederates were in a confused retreat, hoping to goad the Union forces into attacking before they were ready. Rosecrans took the bait and set off in pursuit, allowing his army to become stretched out and disordered into three separate groups, each too far away to support the others. It was just what Bragg wanted, and he moved his troops to cut off and attack an isolated portion of the Federal army, hoping to engage and defeat Rosecrans’ army one piece at a time. The first fight would take place at Chickamauga Creek, ten miles from Chattanooga.
But things did not happen as Bragg had planned. His subordinate officers were slow in moving into position, and the approaching Union force detected the trap and formed a hasty defensive line.
On the morning of September 18, the Confederates crossed the Chickamauga at several points in an attempt to outflank the Federals and cut off their route to Chattanooga. At one point, a brigade of Indiana mounted infantry under Colonel John Wilder, armed with new Spencer repeating rifles, held off a much larger Southern force for five hours before being forced to retreat. By nightfall the Federals had formed a stronger defensive line along the Lafayette Road, where the thick forest made it difficult for neighboring units to see each other or any approaching enemy.
The next morning, Union Maj Gen George Thomas sent one of his brigades forward against what he thought was a single Confederate brigade, but actually concealed in the thick woods was a Southern cavalry division under Gen Nathan Bedford Forrest and an infantry division commanded by a Confederate General with the wonderfully unlikely name States Rights Gist (yes, that was his actual birth name). Hearing this fighting, two more Confederate units, led by Generals Alexander Stewart and John Bell Hood, also attacked. Fortunately for the Federals, two divisions of reinforcements, under Generals Philip Sheridan and Thomas Wood, entered the fight and broke the assault. The Union line held.
Reinforced by Gen James Longstreet’s forces during the night (Longstreet had accidentally stumbled into a group of Union pickets and had almost been captured), Bragg now ordered an attack at dawn the next day, but due to miscommunication the troops, under John Breckinridge, did not move until 9:30 that morning. Although some of the Federal units suffered 30 percent casualties, the Confederates found themselves crossing an open field into Union positions protected by breastworks, and their assault bogged down.
At this point, around 11am, the Confederates were handed a golden opportunity. During the confused fighting in the thick woods and low visibility, Rosecrans received some incorrect information indicating that there was a gap in his line, and ordered troops under Gen Wood to move to plug the non-existent hole. Wood was confused by the order—he could see there was no gap in the line—but pulled out his troops and moved them anyway (he had already been berated by Rosecrans for moving his troops too slowly in the battle, and apparently didn’t want to risk the commander’s wrath by asking for clarification). Wood’s troop movement then created an actual gap in the line, and as it happened Longstreet was already charging in with 23,000 men, aiming towards a small farmhouse in the Union line known as the Brotherton House.
Under this assault, most of the Union line reeled back in disorder. Only the actions of Union Gen Thomas staved off complete disaster: forming a defensive line at Snodgrass Hill, Thomas, though under assault by three brigades, held off the Confederates long enough to allow the rest of the Federal Army to regroup and begin an organized retreat back to Chattanooga. His defensive stand earned him the nickname “The Rock of Chickamauga”.
Chickamauga was one of the bloodiest battles of the war: Rosecrans lost 16,000 men and Bragg lost 18,000. It was the last major Confederate victory in the Civil War, but although a tactical win, it was a strategic failure: the Union troops still held Chattanooga, and soon General Ulysses Grant arrived with reinforcements and captured the entire area. In 1864, General William T Sherman used Chattanooga as the jumping-off point for his march to Atlanta.
The Chickamauga Battlefield is now a National Military Park, run by the National Park Service.