Short answers, pulled from the story.
The Battle of Nashville took place from December 15 to the 16th of December 1864. Confederate forces arrived south of the city on December 2 and Union troops attacked five redoubts guarding the Confederate left flank at 2:30 pm on December 15.
Major General George H. Thomas commanded the combined Union force of approximately 55,000 men during the battle. Major General John M. Schofield led XXIII Corps while Brigadier General James R. Chalmers operated cavalry southwest of the city for the Confederates.
Federal casualties totaled 387 killed, 2,562 wounded, and 112 missing during the battle. The Army of Tennessee entered Middle Tennessee with approximately 38,000 men but reported an effective strength of only 18,742 men on January 20 after severe losses.
The Nashville battlefield encompasses almost all of south and west Nashville today including neighborhoods like Green Hills, Forest Hills, Oak Hill, Lipscomb, and Brentwood. Fort Negley was built between 1862 and 1863 by African Americans forcibly impressed by Union military government and fired the first shots in the battle.
Confederate Lieutenant General John Bell Hood lost the battle because his army suffered severe casualties at Spring Hill, Franklin, and Nashville plus at least 2,000 desertions. He resigned his command on the 13th of January 1865 after retreating to Tupelo, Mississippi and his career ended without another field command.