Vicksburg and Chattanooga
Northern attention focused most sharply on Gettysburg as the battle that foiled the Confederate invasion of the North. However, while that battle was being fought, Union forces under General Ulysses S. Grant were bringing to a conclusion a long and frustrating campaign against Vicksburg, Mississippi, the Confederacy’s seemingly impregnable stronghold on the Mississippi River. The prize here was not just a fortress, but control of the great river. Once the South lost the Mississippi, the Confederacy was split in two, the western states unable to communicate with the East or to supply reinforcements to it. Grant had campaigned—in vain—against Vicksburg during the fall and winter of 1862-63, finally taking it on July 4, 1863.
Grant next turned his attention to Chattanooga, which occupied a critical position in a bend of the great Tennessee River. Union forces under William S. Rosecrans had ousted Braxton Bragg from Chattanooga in early September 1863, but, reinforced, Bragg returned to engage Rosecrans at the Battle of Chickamauga on September 19-20. Bragg fielded 66,001) men against Rosecrans’s 58,000. By the second day of this bloody struggle along Chickamauga Creek in northwestern Georgia, the Confederates had driven much of the Union army from the field in disarray.
Complete disaster was averted by General George H. Thomas, in command of the Union left flank. Moreover, Bragg failed to press his advantage, laying incomplete siege around Chattanooga while also detaching troops to attack Knoxville. By failing to act with greater focus, Bragg allowed Grant sufficient time to arrive, on October 23, and reinforce the Army of the Cumberland (now under Thomas’s command). Sixty thousand Union troops now faced Bragg’s reduced forces—about 40,000 men—in two battles set in the rugged terrain overlooking Chattanooga. The Battle of Lookout Mountain (November 24) was called the “Battle Above the Clouds,” because it was fought at an elevation of 1,100 feet above the Tennessee River—and above a dense line of fog. The Battle of Missionary Ridge followed (November 25). In these two engagements, Thomas and Grant decisively defeated Bragg, with the result that Tennessee and the Tennessee River fell into Union hands.