The Battle of Chickamauga, fought on 19-20 September 1863, was a turning point in the American Civil War. The Union forces, under Maj. Gen. William Rosecrans, were defeated by the Confederate Army of Tennessee, led by Gen. Braxton Bragg, in what would become one of the bloodiest battles of the war in terms of casualties. This battle marked the end of the Union offensive, known as the Chickamauga Campaign, in southeastern Tennessee and northwestern Georgia.

RIGHT: Battle of Chickamauga--Sept. 19' & 20' 1863--Federal ... (Gen. Rosecrans com.) Confederate ... (Gen. Bragg com.) by Kurz & Allison. Source: Library of Congress.

Leading up to the Battle of Chickamauga, Union forces under the command of Major General William Rosecrans sought to secure control over Chattanooga, Tennessee, a crucial transportation and strategic hub for both the Union and the Confederacy. After a series of maneuvers executed during Rosecrans’ Tullahoma Campaign in the summer of 1863, Confederates, led by General Braxton Bragg, retreated from middle Tennessee into northern Georgia. The Union’s ability to capture Chattanooga would potentially grant them control over vital railroads and open a pathway into the heart of the Confederacy.

By mid-September, Rosecrans’s Army of the Cumberland extended dangerously across a broad, fragmented front as they pursued Bragg’s forces southward. Recognizing this vulnerability, General Bragg, commanding the Confederate Army of Tennessee, sought to consolidate his forces and counterattack. Reinforced by troops from Lieutenant General James Longstreet, dispatched from the Army of Northern Virginia, Bragg prepared to deliver a decisive blow to the Union troops near the banks of Chickamauga Creek in Georgia.

The Battle of Chickamauga was a significant victory for the Confederacy, as it halted the Union's advance into southern territory and prevented them from taking the city of Chattanooga. It was also the first major battle fought in Georgia during the Civil War. The battle involved the second-highest number of casualties after the Battle of Gettysburg, with over 34,000 casualties and over 18,000 killed or wounded.

The conflict began when Rosecrans, following his successful Tullahoma Campaign, renewed his offensive against Bragg's army in Chattanooga. Bragg was determined to reoccupy Chattanooga and decided to meet and defeat part of Rosecrans's army in the hopes of moving back into the city. On September 18, 1863, as Bragg headed north, his cavalry and infantry engaged with Union cavalry and mounted infantry, who were armed with Spencer repeating rifles, at Alexander's Bridge and Reed's Bridge.

Fighting started on the morning of September 19 when Bragg's men strongly assaulted but could not break the Union line. The next day, Bragg resumed his assault, and Rosecrans was misinformed that he had a gap in his line. By moving units to shore up the supposed gap, Rosecrans created an actual gap directly in the path of an eight-brigade assault on a narrow front by Confederate Lt. Gen. James Longstreet. In the resulting chaos, Longstreet's attack drove one-third of the Union army, including Rosecrans himself, from the field.

Skirmishes erupted in the dense woods near Chickamauga Creek on the morning of September 19 as both sides scrambled to secure key terrain. Rosecrans attempted to gather his extended lines into a more cohesive formation, but communication delays and dense forested terrain complicated these efforts. Meanwhile, Bragg initiated aggressive assaults, directing his forces to attack the Union left flank near Jay’s Mill and Vineyard Field. Over the course of the day, heavy fighting spread across the battlefield, marked by confusion caused by dense terrain and obscured sightlines.

The first day concluded indecisively, with neither side able to secure a decisive advantage. However, Bragg’s reinforced Confederate forces retained momentum and positioned themselves to launch stronger attacks the following day.

Despite the retreat, Union units spontaneously rallied to create a defensive line on Horseshoe Ridge, forming a new right wing for the line of Maj. Gen. George H. Thomas, who assumed overall command of remaining forces. Although the Confederates launched costly and determined assaults, Thomas and his men held until twilight. Union forces then retired to Chattanooga while the Confederates occupied the surrounding heights, besieging the city.

RIGHT: Lee and Gordon's Mills, Chickamauga Battlefield, Tenn. Source: National Archives: Record Group 111: Records of the Office of the Chief Signal Officer Series: Mathew Brady Photographs of Civil War-Era Personalities and Scenes.

On the second day, Bragg sought to exploit weaknesses in the Union line. A critical moment occurred when a series of miscommunications within the Union leadership created a gap in their defensive line. Acting on faulty information, Rosecrans ordered the repositioning of a division, inadvertently leaving an opening in the Union ranks.

Seizing this opportunity, Longstreet’s Confederate corps launched a massive assault on the Union center, driving it into disarray. The attack forced portions of Rosecrans’s army, including himself, to retreat to Chattanooga in chaotic withdrawal. However, not all Union forces crumbled. On the northern flank, Major General George H. Thomas, commanding a portion of the Union Army, orchestrated a resolute last stand on Snodgrass Hill and Horseshoe Ridge. His steadfast defense earned him the nickname “The Rock of Chickamauga.”

Despite Thomas’s heroic efforts, the Union army suffered significant losses, retreating from the field. The Confederates secured a tactical victory but failed to pursue the Union forces quickly or effectively capitalize on their success.

The aftermath of the battle had significant consequences. Rosecrans's army withdrew to Chattanooga and established strong defensive positions, but the supply lines into Chattanooga were at risk, and the Confederates soon occupied the surrounding heights, laying siege upon the Union forces. Rosecrans was relieved of his command of the Army of the Cumberland, replaced by Thomas, and other officers also lost their commands. On the Confederate side, Bragg began waging a battle against his subordinates, suspending both officers from their commands.

The Battle of Chickamauga was one of the deadliest engagements of the American Civil War, resulting in staggering losses on both sides. The Union suffered a total of 16,170 casualties, including 1,657 soldiers killed, 9,756 wounded, and 4,757 captured or missing. Likewise, the Confederate Army experienced a harrowing toll of 18,454 casualties, with 2,312 soldiers killed, 14,674 wounded, and 1,468 captured or missing. Among the notable casualties of the Battle of Chickamauga were prominent Confederate generals, including Benjamin Hardin Helm, James Deshler, and Preston Smith, and Union General William H. Lytle. Additionally, Confederate General John Bell Hood was severely wounded, receiving a bullet in his leg that required amputation. This tragic outcome was particularly devastating for Hood, who had already lost the use of his left arm due to a prior wound sustained during the Battle of Gettysburg.  

The Confederacy succeeded in halting the Union advance, preserving northern Georgia under Confederate control for the time being. However, the strategic significance of this victory was partially diminished by logistical difficulties and leadership dysfunction within Bragg’s command structure.The Union army’s retreat to Chattanooga set the stage for the subsequent Battles of Chattanooga two months later, where Union forces, reinforced under the command of Ulysses S. Grant, would achieve a decisive victory. This shift in momentum opened a pathway for General William T. Sherman’s Atlanta Campaign and the infamous March to the Sea.

Bibliography

Foote, Shelby. The Civil War: A Narrative: Fredericksburg to Meridian. New York: Random House, 2011.

McPherson, James M. Battle Cry of Freedom: The Civil War Era. Oxford: Oxford University Press, 2003.

Robertson, William G. River of Death: The Chickamauga Campaign: Volume 1: The Fall of Chattanooga. Chapel Hill: UNC Press Books, 2018.

Sheehan-Dean, Aaron, editor. The Cambridge History of the American Civil War. Cambridge: Cambridge University Press, 2019.