The evening of August 31st, Bragg received a report that the main force of Rosecrans’s army was crossing the Tennessee River at points 22 and 32 miles southwest of Chattanooga. Unopposed on today's date in 1863, large Federal forces were now in the Wills Valley, west of Lookout Mountain. Part of the Union army was reported to be moving south in the valley, and perhaps would cross the mountain at Winston’s Gap, 42 miles from Chattanooga, in an attempt to cut off the Confederate supply line from Atlanta. Learning of this threat to the rear of his army, Bragg will abandon Chattanooga on September 8, and the next day the Federals will occupy the city.
Great Grandfather's division's commanding general, Patrick Cleburne, advised the army's commander-in-chief, Gen. Braxton Bragg, that he should attack and crush the enemy corps facing him. However, Bragg did not agree and passed up an important opportunity.