General Ormsby Mitchel[U.S.], advanced to Huntsville, Alabama in the Spring of 1862. On April_12, 1862 spies under his command led by civilian James Andrews stole the locomotive The General in Big Shanty, Georgia, planning to destroy bridges between Atlanta and Chattanooga on the Western and Atlantic Railroad. Theoretically, this would leave Chattanooga without supplies and reinforcements, making it easier for Mitchel to advance and capture the city. Andrews and his men rode it to Ringgold in an episode known today as "The Great Locomotive Chase." Pushed beyond its limits, the engine came to a halt 2 miles north of the Ringgold Depot. Mitchel never advanced to the city and the Union spies on this adventure were the first to receive the Medal of Honor.
On June 7th, 1862, men under the command of James Negley moved into position along the northern shore of the Tennessee River opposite Cameron Hill. The troops withdrew the following day after running into Rebels under the command of Major General Edmund Kirby Smith.
On August_21, 1863, men under the command of Colonel John T. Wilder [U.S.] moved into position northeast of the city. They began pounding Chattanooga with artillery shells. Over the next two weeks the attacks continued until Braxton Bragg was forced to retreat, because, distracted by the shelling from the northeast, Bragg had been outflanked. Retreating to protect his lifeline, the Western and Atlantic Railroad, Bragg surrendered the city without a shot being fired.
Union wagons fill the streets of Chattanooga, Tennessee, during the Civil War
After the defeat of the Union Army during the battle of Chickamauga, William S. Rosecrans retreated to the Scenic City, which was quickly surrounded by the Confederate Army. At first, the men were afraid they would lose the city. Lincoln sent Ulysses S. Grant to take command, with orders to keep the city in Union hands at all costs. Grant immediately set about the task.
A daring attack at Brown's Ferry west of the city opened up what became known as "The Cracker Line," a supply route between the besieged city and the Union stronghold of Bridgeport, Alabama. Grant would use this route to resupply Chattanooga. A confused nighttime attack by James Longstreet at Battle of Wauhatchie was, according to Longstreet, merely an attempt to gain supplies for the Rebels on Lookout Mountain.
With the Rebel Army controlling high points to the south (Lookout Mountain) and east (Missionary Ridge) of Chattanooga, Grant ordered General Joseph "Fighting Joe" Hooker to take the mountain, which he did on November_24, 1863. This highly romanticized skirmish became known as the "Battle Above the Clouds" because of the unusual fog that settled about halfway up the mountain during the battle.
The following day Grant ordered Hooker and William Tecumseh Sherman to attack the flanks of Bragg's Army of Tennessee while General George Thomas demonstrated in front of the Rebels. Neither Hooker nor Sherman were successful at turning either flank of Bragg's Army. Thomas then took Missionary Ridge with a frontal assault, routing the Confederates. The battles for Chattanooga were over.
Following the final battle for Chattanooga, Ulysses S. Grant left for Washington D. C., where he would assume command over the entire Union Army. Sherman, Hooker and Thomas stayed on, preparing for the next series of battles in the Western Theater of Operations, The Atlanta Campaign.