The key positions of the whole movement were the passes in Missionary Ridge, which controlled the roads to Chattanooga, and these lay less than two miles from the field, and directly on the roads both armies were pushing over toward the city.
The history of the fighting is well known. The breaking of the right on the second day has been widely treated as if it were the rout of the Union forces. But Thomas, who remained with the largest part of the army intact, fought through to the close of the battle with his lines unbroken. The last divisions of our line to leave the field were in undisturbed possession of their ground, and withdrew quietly and unmolested. Thomas left the field mainly because the passes which controlled Chattanooga—the objective point of the campaign—were in his rear, and if he did not occupy them that night the chances were that the rebels would do so, and thus make successful their plan of battle, which was to turn the Union left and interpose between Rosecrans and Chattanooga.
The rebels did not follow till noon of the next day, and finding our army in the passes did not attack it. The following day Rosecrans' army marched undisturbed into Chattanooga, and Union troops held it till the close of the war.
Chickamauga, then, was the battle for Chattanooga; and at the end of a campaign which, when impartial history is written, will assuredly rank among the most brilliant for its strategy, the prize for which Rosecrans contended was won. The troops which fought longest and suffered most never looked upon the battle as a defeat, and were fully satisfied with the part they had played. To the Army of the Cumberland it was but the battle for, and the winning of Chattanooga, And this, though Sherman's readers would not dream of it, is how it came to pass that ‘Bragg had completely driven Rosecrans' army into Chattanooga.’