In late June 1863, Union Major General William S. Rosecrans launched a major offensive from Murfreesboro to drive Confederate General Braxton Bragg’s 43,000-man Army of Tennessee from its entrenchments at Shelbyville and Wartrace and possibly out of the state, while aiming to capture Chattanooga and “rescue loyal East Tennessee from the hands of the rebels.” Rosecrans divided his army into four independent columns to maneuver Bragg out of his Shelbyville trenches: one advanced south from Murfreesboro to threaten the main Confederate infantry at Shelbyville, another moved through Liberty Gap, a third marched southeast down the Manchester Pike toward Chattanooga, and a fourth went east along the McMinnville Turnpike before turning south to cross the Highland Rim below Bradyville at Gillie’s Gap. By June 28, the bulk of the Union army was in Manchester, and the Union also held Shelbyville and Bragg’s entrenched lines. Despite rain and poor roads, Rosecrans continued the advance toward Tullahoma. Bragg crossed the Elk River at Allisonia on June 30 and began a general retreat, briefly establishing headquarters at Dechard before moving up the Cumberland Plateau. By July 4, the Union’s 70,000-strong Army of the Cumberland had forced the Confederates back to Chattanooga, leaving nearly all of Tennessee in Union hands, and Union cavalry under Philip Sheridan had pushed Confederate skirmishers out of Winchester and reached Cowan after Bragg had moved over the Plateau.