The Battle of Nashville was a two-day battle in the Franklin-Nashville Campaign that represented the end of large-scale fighting west of the coastal states in the American Civil War. It was fought at Nashville, Tennessee, on December 15–16, 1864, between the Confederate Army of Tennessee under Lieutenant General John Bell Hood and the Union Army of the Cumberland (Dept. of the Cumberland) (AoC) under Major General George H. Thomas. In one of the largest victories achieved by the Union army during the war, Thomas attacked and routed Hood's army, largely destroying it as an effective fighting force.

Hood followed up his defeat in the Atlanta Campaign by moving northwest to disrupt the supply lines of Maj. Gen. William T. Sherman from Chattanooga, hoping to challenge Sherman into a battle that could be fought to Hood's advantage. After a brief period in which he pursued Hood, Sherman decided instead to cut his main army off from these lines and "live off the land" in his famed March to the Sea from Atlanta to Savannah. By doing so, he would avoid having to defend hundreds of miles of supply lines against constant raids, through which he predicted he would lose "a thousand men monthly and gain no result" against Hood's army. Sherman disengaged and turned east, leaving the matter of Hood's army and the defense of Tennessee to Thomas. Hood devised a plan to march into Tennessee and defeat Thomas's force while it was geographically divided. He pursued Maj. Gen. John M. Schofield's army from Pulaski to Columbia and then attempted to intercept and destroy it at Spring Hill. Schofield had been tasked by Thomas with delaying Hood as much as possible, without losing his army, while Thomas pulled in his forces to concentrate at Nashville. Because of a series of Confederate command miscommunications and solid U.S. Army leadership in the Battle of Spring Hill (November 29, 1864), Schofield was able to withdraw from Columbia and slip past Hood's army at Spring Hill relatively unscathed.

Furious at his failure at Spring Hill, Hood pursued Schofield to the north and encountered the Union at Franklin behind strong fortifications. In the Battle of Franklin on November 30, Hood ordered almost 31,000 of his men to assault the Union works before Schofield could withdraw across the Harpeth River and escape to Nashville. Schofield and his men were intent on getting across the Harpeth and really did not expect Hood and his army to attack; the fact that they did attack with such ferocity soon made the U.S. troops realize that they had changed from a delaying action to a desperate fight for survival. The Union soldiers repulsed multiple assaults and inflicted over 6,000 casualties on the Confederates, which included a large number of key Confederate generals, doing heavy damage to the leadership of the Army of Tennessee.

Schofield withdrew from Franklin during the night and marched into the defensive works of Nashville on December 1, there coming under the command of Thomas, who now had a combined force of approximately 55,000 men. By and large, his troops were veterans, the IV Corps under Brig. Gen. Thomas J. Wood and Schofield's XXIII Corps having fought in the Atlanta campaign and Maj. Gen. Andrew J. Smith's "Detachment of the Army of the Tennessee" (a part of the recently discontinued XVI Corps had been redesignated with this unusual name on December 6) having fought at Vicksburg, in the Red River Campaign, at Tupelo against S.D. Lee and Nathan Bedford Forrest, and in Missouri against Sterling Price. While Wilson's cavalry had combat experience, most of it had been of the wrong kind at the hands of Nathan Bedford Forrest, John Hunt Morgan, or Joe Wheeler. Only Maj. Gen. James B. Steedman's Division lacked experience fighting together. It was composed of garrison troops and railroad guards from Tennessee and Georgia and included eight regiments of United States Colored Troops.

Union forces had been constructing defensive works around Nashville since the time the city was occupied in February 1862. By 1864, a 7-mile-long semicircular Union defensive line on the south and west sides of the city protected Nashville from attacks from those directions. The line was studded with forts, the largest being Fort Negley. The trench line was extended to the west after December 1. The Cumberland River formed a natural defensive barrier on the north and east sides of the city. Smith's troops had arrived by river on November 30, and their transports had been escorted by a powerful fleet of tinclad and ironclad gunboats. Thus, the river barrier was well-defended.

From east to west the defensive line was manned by Steedman's division, the XXIII Corps, the IV Corps, and Smith's XVI Corps Detachment. During the amassing of his forces and the construction of his defenses, Thomas' troops punctuated their entrenching with small offensive operations and raids.Given the fact that the Union army was composed of troops from the Army of the Cumberland, the Army of the Ohio, the Army of the Tennessee, the District of Etowah, and the Post of Nashville, the force in Nashville had no official name.

Hood's Army of Tennessee arrived south of the city on December 2 and took up positions facing the Union forces within the city. As he was not nearly strong enough to assault the Union fortifications, Hood opted for the defensive. Rather than repeating his fruitless frontal attack at Franklin, he entrenched and waited, hoping that Thomas would attack him. Then, after Thomas had smashed his army against the Confederate entrenchments, Hood could counterattack and take Nashville.

The Confederate line of about four miles of fortifications faced the southerly facing portion of the Union line (the part occupied by Steedman and Schofield). From right to left were the corps of Maj. Gen. Benjamin F. Cheatham, Lt. Gen. Stephen D. Lee, and Lt. Gen. Alexander P. Stewart. Cavalry commanded by Brig. Gen. James R. Chalmers was off to the southwest of the city. The Confederate left flank was secured by five small detached redoubts, each having two to four guns with garrisons of about 150 men each. The weather turned cold and many Confederate soldiers took shelter in simple pits which were just big enough for two or three men to sleep alongside each other with a small fire at one end. Alabama soldier Edgar Jones wrote that while he enjoyed the warmth of his new home it gave him "a sort of graveyard feeling" since the shelters were remarkably similar to graves.