American Civil War: The Battle of Nashville ends as the Union Army of the Cumberland under General George H. Thomas routs and destroys the Confederate Army of Tennessee under General John Bell Hood, ending its effectiveness as a combat unit.

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 (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.

The Union was the central government of the United States during the American Civil War. Its civilian and military forces resisted the Confederacy's attempt to secede following the election of Abraham Lincoln as president of the United States. Lincoln's administration asserted the permanency of the federal government and the continuity of the United States Constitution.

The Army of the Cumberland was one of the principal Union armies in the Western Theater during the American Civil War. It was originally known as the Army of the Ohio.

George Henry Thomas was an American general in the Union Army during the American Civil War and one of the principal commanders in the Western Theater.

John Bell Hood was a Confederate general during the American Civil War. Hood's impetuosity led to high losses among his troops as he moved up in rank. Bruce Catton wrote that "the decision to replace Johnston with Hood was probably the single largest mistake that either government made during the war." Hood's education at the United States Military Academy led to a career as a junior officer in the infantry and cavalry of the antebellum U.S. Army in California and Texas. At the start of the Civil War, he offered his services to his adopted state of Texas. He achieved his reputation for aggressive leadership as a brigade commander in the army of Robert E. Lee during the Seven Days Battles in 1862, after which he was promoted to division command. He led a division under James Longstreet in the campaigns of 1862–63. At the Battle of Gettysburg, he was severely wounded, rendering his left arm mostly useless for the rest of his life. Transferred with many of Longstreet's troops to the Western Theater, Hood led a massive assault into a gap in the Union line at the Battle of Chickamauga but was wounded again, requiring the amputation of his right leg.