The Chickamauga Campaign

In Tennessee in the summer of 1863, the Union Army of the Cumberland under William Rosecrans was still facing Braxton Bragg's Army of Tennessee. In the Tullahoma Campaign Rosecrans had brilliantly outmaneuvered Bragg and nearly without bloodshed forced him back to Chattanooga, on the Tennessee-Georgia border. Rosecrans did not follow Lincoln's instructions and continue to press the Confederates. The Confederate army held an important position at Chattnooga. It was surrounded by mountains, and was an important rail hub – the gateway to the southern heartland. There was much dissension in the Confederate command. Bragg had won some successes as a combat commander, but had alienated his subordinates by his unpleasantness and his tendency to retreat after victories. President Davis urged him to go on the offensive, but the terrain was difficult in the area, and he would rather wait for Rosecrans to move against.

Rosecrans

Towards the end of August that's just what happened. Rosecrans sent a cavalry unit called the Lightning Brigade, who were armed with repeating rifles and commanded by John Wilder to distract Bragg. They were positioned to the northeast of Chattanooga, and began shelling the town over several weeks. Meanwhile the rest of the Union army moved to the southwest of the city. When Bragg realized that he had been duped, he thought he had no choice but to retreat, abandoning Chattanooga on September 6th.

As the Confederates retreated into northern Georgia, Rosecrans pursued with three columns. He believed that the rebels were demoralized, and allowed his units to become separated in the mountainous terrain. The center Union column under George Thomas had rushed forward to seize mountain gaps, and Bragg ordered an attack on his men's position at Davis's Cross Roads in the front and flank. But expected reinforcements did not arrive to the units directed to make the attack, and their commanders agreed not to strike. Next morning more troops did arrive, but by that time the Union forces had been strengthened, and fell back skirmishing with the Confederates, having got word of the attack.

Bragg

In this mangled movement the Confederates had missed a major opportunity, and Bragg was infuriated with the failure of his subordinates to obey orders. Bragg turned his focus to try to isolate and attack the left-most column of the Federal advance. In this movement his ranks would be greatly strengthened. The Confederate War Department had decided to reinforce him with James Longstreet's First Corps from Robert E. Lee's Army of Northern Virginia. They would arrive by train in a few days, nearly stepping off of the cars into battle. In a council of war on September 15th Bragg and the other Confederate generals agreed on an advance towards Chattanooga and Rosecrans's rapidly concentrating army. This movement would culminate in a battle along Chickamauga Creek. Due to the sudden arrival of the Confederate reinforcements, the southerners would have the numerical advantage, one of the few times in the entire war.