Two days of fighting that ended a Confederate invasion of Tennessee in 1864, and effectively destroyed the army that had launched that invasion (American Civil War). That invasion had been launched by General John Hood after the fall of Atlanta. He hoped that by moving north he would force the Union army under General Sherman to retreat from Georgia to deal with the threat to its supply lines. Instead, Sherman had already decided to abandon those supply lines, and take 62,000 of his men east to the Atlantic coast. The rest of the army was sent north under General Thomas, to oppose Hood.
Hood had crossed into Tennessee with 40,000 men. Thomas had 60,000 men, although 30,000 of them were rather scattered around the southern part of the state, protecting the long lines of communication across the mostly hostile state. However, Hood had missed two chances to trap most of those troops (under General Schofield). In frustration he had launched a frontal assault on Schofield at Franklin (30 November). There, he had suffered massive casualties, including five dead Generals, and at least 5,000 other losses (probably more, maybe as many as 7,000).
Despite these losses, Hood did not feel that he could risk a retreat. Many of his men were from Tennessee. Hood was concerned that many of them would desert rather than leave their home state for a second time. Accordingly he advanced towards Nashville, taking up a position four miles south of the town. His best hope now was that reinforcements would reach him, but none did. Despite that, he still had around 39,000 men at Nashville (30,000 infantry and 9,000 cavalry). When Thomas attacked, Hood would not be hopelessly outnumbered.
That attack was delayed. The early December weather was terrible, slowing Thomas’s preparations, which were not all that fast in the first place. The sight of a Confederate army threatening a position so far north so soon after Lincoln’s re-election was desperately embarrassing. Thomas was bombarded with messages from Grant, asking why he had not attacked yet, ordering him to attack, and even threatening to replace him.
Finally, on 14 December the weather improved enough for Thomas to announce that the attack would take place on the next day. His plan was fairly simple. He slightly outnumbered Hood on the day, with 43,000 effective soldiers in combat (out of a total force of 55,000 around Nashville, some of whom played a passive role in the battle by preventing some Confederate movements).
The first attack would be on the Confederate right. The aim of this attack was simply to pin those troops in place, preventing them from moving to the aid of the Confederate left, where the main Union effort was to be made. There an entire army corps, supported by the cavalry, was to attempt to work its way around the Confederate left. If the movement succeeded, the Confederate left would be attacked from front and rear, and would almost inevitably collapse.
This plan did not succeed on 15 December. Instead, the Confederate left was pushed back, creating an angle in their line which made it much harder to outflank. However, Hood was forced to pull back to a shorter line overnight. The following day saw renewed Union attacks, which eventually met with success in mid-afternoon. Union cavalry finally managed to get behind Hood’s left wing, and combined with another assault from the front routed the left wing. The rout quickly spread along the entire line. In Hood’s own works, ‘.. I beheld for the first and only time a Confederate Army abandon the field in confusion.’ (Hood had missed the similar disaster at Missionary Ridge).
This second disaster, coming so soon after the battle of Franklin, marked the end of the Confederate Army of Tennessee. Over the next two weeks the survivors of the battle struggled back south. Some order was soon restored, although even Hood was not deluded enough to attempt to turn and stand. Without Forrest’s cavalry, very few of the 40,000 men who had marched north would have returned to Alabama. Even with that cover, when the army finally reached relative safety at Tupelo, Mississippi, only 21,000 men remained. Hood had lost some 15,000 men in the fighting at Nashville and the retreat that followed. Union losses were only 3057 (387 dead, 2558 wounded and 112 missing or captured). On 13 January Hood resigned from his command. The great hopes that he had carried north only a few weeks earlier had now turned into the deepest pessimism across much of the south.