The Battle of Hoover's Gap was the principal battle fought in the Tullahoma Campaign of the American Civil War.

Following the Battle of Stones River, Maj. Gen. William S. Rosecrans, commanding the Army of the Cumberland, remained in the Murfreesboro, Tennessee, area for over five months. In an effort to block further Union progress, Gen. Braxton Bragg, commander of the Army of Tennessee, established a fortified line along the Duck River from Shelbyville to Wartrace. On the Confederate right, infantry and artillery detachments guarded Liberty, Hoover’s, and Bellbuckle gaps through the mountains. Rosecrans’ superiors, fearing that Bragg might detach large numbers of men to help break the Siege of Vicksburg, urged him to attack the Confederate positions.

On June 23, 1863, Rosecrans deployed forces to feign an attack on Shelbyville while massing forces against Bragg’s right. His troops struck out toward the gaps, Maj. Gen. George H. Thomas' men, on the 24th, forced Hoover’s Gap. The Confederate 3rd Kentucky Cavalry Regiment, under Col. J.R. Butler, held Hoover’s Gap, but the Federals easily pushed it aside. As this unit fell back, it ran into Brig. Gen. Bushrod R. Johnson’s and Brig. Gen. William B. Bate’s Brigades, Stewart’s Division, Hardee’s Corps, Army of Tennessee, which marched off to meet Thomas and his men. Fighting continued at the gap until just before noon on the 26th, when Maj. Gen. Alexander P. Stewart, the Confederate division commander, sent a message to Johnson and Bate stating that he was pulling back and they should also. Although slowed by rain, Rosecrans moved on, forcing Bragg to retreat from his defensive line and fall back to Tullahoma. Rosecrans sent a flying column (Wilder’s Lightning Brigade, the same that had spearheaded the thrust through Hoover’s Gap on the 24th) ahead to hit the railroad in Bragg’s rear. Arriving too late to destroy the Elk River railroad bridge, the Federals destroyed railroad track around Decherd. Bragg then evacuated his forces from Middle Tennessee.

Hoover's Gap was an unambiguous Union battlefield victory and strategic advance.

Reference

Nation Park Service