Fought from November 23 through November 25, 1863, the Battle of Chattanooga ended Confederate General Braxton Bragg's investment of Federal troops at Chattanooga and paved the way for for the Union's successful Atlanta Campaign in 1864.
On December 26, 1862, Major General William S. Rosecrans led the Union Army of the Cumberland out of Nashville, Tennessee with orders to capture Chattanooga, Tennessee. Chattanooga was an important railroad junction that connected the upper Confederacy with the Deep South. Between Rosecrans and Chattanooga was Lieutenant General Braxton Bragg and the Confederate Army of Tennessee. On December 31, the two armies clashed at the Battle of Stones River (December 31, 1862 to January 2, 1863) near Murfreesboro, Tennessee. The Union army prevailed, and Bragg retreated south towards Tullahoma, Tennessee. In June, the Federals moved on the Rebels at Tullahoma, forcing Bragg to withdraw his army to Chattanooga.
In mid-August, Rosecrans prepared to assault Chattanooga, but a series of maneuvers on his part convinced Bragg that the city was indefensible. On September 9, Bragg abandoned Chattanooga and led the Army of Tennessee through the mountains into northern Georgia. Although Rosecrans had achieved his objective of capturing Chattanooga, he decided to pursue Bragg’s army into Georgia. Stung by criticism that he received for abandoning Chattanooga, Bragg was determined to win the city back. On September 19, the Army of Tennessee attacked the Union Army of the Cumberland at the Battle of Chickamauga (September 19-20, 1863). Bragg’s army drove the Federals back toward Chattanooga, forcing them to occupy the defensive works previously constructed by the Rebels. Bragg seized the high ground overlooking Chattanooga (Lookout Mountain, Seminary Ridge and Raccoon Mountain) and laid siege to the city.
Due to the Army of the Cumberland’s dire situation, Northern authorities sent twenty thousand soldiers under the command of General Joseph Hooker, as well as sixteen thousand men that General William T. Sherman led, to assist the Army of the Cumberland. Officials placed General Ulysses S. Grant in command of all Northern soldiers in the vicinity of Chattanooga and also replaced Rosecrans with General George Thomas as the commander of the Army of the Cumberland.
With the arrival of some of the reinforcements in late October 1863, Grant immediately embarked upon a plan to alleviate the supply woes of the Army of the Cumberland. By October 28, Grant’s men managed to open a narrow supply line that became known as the “Cracker Line.” Northern Brigadier-General William F. Smith had proposed the line, but Rosecrans had failed to act on his subordinate’s recommendation. Grant endorsed the plan, and thanks to Confederate General James Longstreet’s refusal to attack the Northern forces carrying out the movement, Union soldiers established the supply line. At Commanding General Braxton Bragg’s orders, Longstreet did finally launch a night attack on October 28 and the early morning hours of October 29. Longstreet sent in far fewer men against the Union position, which was commanded by General Hooker, than Bragg had ordered. Known as the Battle of Wauhatchie, Hooker’s response was confused, but Union forces managed to hold the position. Longstreet’s failure prompted Bragg to dispatch Longstreet and his men to eastern Tennessee to deal with a potential Northern threat. This action greatly weakened Bragg’s army.
Following the opening of the Cracker Line and the Battle of Wauhatchie, Grant began planning an assault on the Confederate forces. He intended to wait until Sherman’s men arrived on the battlefield. Sherman’s men began to arrive on November 20, but the vast majority of the force was delayed. On November 23, rumors circulated through Northern lines that the Confederate forces were retreating. Grant ordered General Thomas to reconnoiter the center of the Confederate line at the base of Missionary Ridge. Early in the afternoon, fourteen thousand Northern forces under Brigadier-General Thomas J. Wood easily overpowered the six hundred Confederates at Orchard Knob. Initially, Grant had ordered the men to return to Northern lines, but upon seeing the ease the Union men had in securing the position, he ordered his soldiers to hold the position and to entrench.
Union forces continued their assault on the Confederate position the next day. On November 24, General Hooker’s men attacked Confederate forces on Lookout Mountain, which was located on the Southerners’ left flank. By mid afternoon the Union assault had stalled, primarily due to a thick fog that enveloped the mountain, causing soldiers to nickname the Battle of Lookout Mountain as the Battle Above the Clouds. Although Hooker’s men did not take the mountain, he correctly predicted that Southern forces would withdrawal from the mountain that night.
Bragg concentrated his Confederate soldiers on Missionary Ridge. On November 25, Grant chose to assault this Southern position. Sherman, who still did not have his entire force on the battlefield, was to attack the Confederate right flank, while Hooker was to make some demonstrations against the left flank but was not to launch a determined assault. Hooker did, slowly pushing Confederate forces north along Missionary Ridge. General Thomas, who led the Northern troops across from the center of the Confederate line, was to assist Sherman in his assault. Unfortunately for Grant, Sherman’s advance was slowed by stiff Confederate resistance. Late in the afternoon, Grant ordered Thomas to advance against the Confederate center, but he only wanted the Army of the Cumberland to take Southern rifle pits at the bottom of Missionary Ridge. Thomas’s men advanced, seized the rifle pits, and then proceeded, against their original orders, to drive the Confederates from Missionary Ridge. Bragg’s army retreated from the ridge, finishing the Battle of Chattanooga.