Fought from September 19 to September 20, 1863, the Battle of Chickamauga produced the highest casualty totals for any battle in the western theater of the American Civil War and second only to the Battle of Gettysburg for the entire war.
Following the Battle of Perryville (October 8, 1862), General Braxton Bragg called off his Confederate Heartland Offensive and withdrew his soldiers from Kentucky to Tennessee. There, Bragg merged forces with General Kirby Smith’s Army of Kentucky and reorganized his command to form the Army of Tennessee. In November, Bragg established a defensive position along the West Fork of the Stones River, near Murfreesboro, intent on preventing a Union advance on Chattanooga.
Rosecrans Replaces Buell
Frustrated because the Union forces did not immediately pursue Bragg during his retreat from Kentucky, President Abraham Lincoln relieved Major General Don Carlos Buell of his command and placed Major General William Rosecrans in charge of the newly formed Army of the Cumberland on October 24, 1862. Upon Rosecrans’ promotion, Union General-In-Chief Henry Halleck cautioned him that “… the Government demands action, and if you cannot respond to that demand some one else will be tried.”
Rosecrans quickly established headquarters in Nashville and prepared his army for battle. On December 26, Rosecrans left Nashville with about 44,000 men prepared to engage Bragg’s army of about 38,000 soldiers encamped at Murfreesboro.
Battle of Stones River
Between December 31 and January 2, the two armies clashed at the Battle of Stones River, near Murfreesboro, Tennessee. The Union army suffered higher casualties than the Rebels, but Bragg retreated when Federal reinforcements began arriving on the site. On January 3, the Army of Tennessee withdrew to Tullahoma, Tennessee, thirty-six miles to the south, yielding Murfreesboro to Rosecrans.
Bragg Abandons Chattanooga
The two armies did not confront each other again until June when Rosecrans moved toward Tullahoma. There, Rosecrans cleverly outmaneuvered Bragg, forcing the Confederate army to retreat to the relative safety afforded by the mountainous terrain and Tennessee River at Chattanooga. Rosecrans followed, and by mid-August, the Army of the Cumberland was on the outskirts of Chattanooga.
Once again, Rosecrans outmaneuvered Bragg. By sending a column of Federals upriver, a few miles north of Chattanooga, Rosecrans convinced Bragg that he intended to cross the river and attack from that direction. Meanwhile, the bulk of the Union army was crossing the Tennessee River below the city. By September 1, the Army of the Cumberland had crossed the Tennessee River with no resistance. Realizing that his army was once again in peril, Bragg abandoned Chattanooga on September 9, 1863, marching his soldiers into northern Georgia.
Rosecrans Pursues Bragg into Georgia
Rosecrans had achieved his goal of capturing Chattanooga, but rather than regrouping and securing the city as he had done at Murfreesboro, he pursued Bragg’s army into Georgia. Initially, Rosecrans deployed his army as three separate corps. During the second week of September, Bragg missed several opportunities to inflict damage on the isolated units. Rosecrans eventually identified his vulnerability and scrambled to reunite the Army of the Cumberland.
September 18 – Bragg Strikes Back
On September 18, the Confederates assaulted several crossing points on Chickamauga Creek that Federal troops held. Union resistance was fierce, and although the Rebels eventually crossed the creek, they did not do so in time to launch a full-scale attack that day.
September 19 – The Main Battle Begins
The main battle began on September 19 when Bragg ordered a major assault on the Union left. By the middle of the day, heavy fighting erupted between the middle of both lines. Despite repeated attacks from the Confederates, the Federals held their position throughout the day. That night, they pulled back and constructed log breastworks along a new line.
September 20 – Union Forces Retreat
On September 20, Bragg renewed the attack. During the late morning, Rosecrans mistakenly believed that the Rebels had created a gap on his left flank. He responded by sending reinforcements from his center, inadvertently creating a real gap there. General James Longstreet immediately exploited the new gap and drove one-third of the Union army, including Rosecrans, from the field. General George H. Thomas took command of the remaining army and withstood Rebel assaults until nightfall and then retreated to the safety of the mountains.
September 21 – Rosecrans Returns to Chattanooga
On September 21, the Army of the Cumberland withdrew to Chattanooga and took up positions in the defensive works previously constructed by Bragg’s army. Bragg responded by seizing the high ground overlooking Chattanooga (Lookout Mountain, Missionary Ridge, and Raccoon Mountain) and laid siege to the city.
The Battle of Chickamauga was costly for both sides. The Union army suffered over 16,000 casualties (killed, wounded, and captured or missing). The Confederates suffered over 18,000 casualties. The combined losses were the highest total for any battle in the western theater of the American Civil War and second only to Gettysburg for the entire war. Bragg won the battle by forcing Rosecrans to retreat, but he did not achieve his strategic goal of recapturing Chattanooga.