Adam Badeau, Military history of Ulysses S. Grant from April 1861 to April 1865. Volume 1

[438] and its branches, they effectually closed the rich valley to the rebels, who were greatly in need of its abundant supplies of grain and beef, and who, besides, had more than once issued through this sally-port on devastating raids, as far north even as the Ohio. Chattanooga, therefore, was an immense bastion at the centre of Grant's line, flanked on one side by the Tennessee valley, and on the other by the mountains of northern Georgia and Alabama. In its front, but a hundred and fifty miles south, lay Atlanta, at the junction of as many important railroads as Chattanooga; and, covered by Atlanta, were Selma, with its arsenals, Montgomery, with its great stores of cotton, Macon, Mobile, and all the rich central valley that extends from the Cumberland mountains to the Gulf of Mexico.

On the 23d of September, immediately after the defeat of Rosecrans, Halleck detached the Eleventh and Twelfth corps from the Army of the Potomac, and sent them by rail, under command of Major-General Hooker, to protect Rosecrans's railroad line of communication between Bridgeport and Nashville. These troops, however, were not ordered further than Bridgeport, as their presence at Chattanooga would only have increased the embarrassment of those who could not themselves be fully supplied. The Army of the Cumberland, therefore, knew that two corps of national troops lay within fifty miles, but unable to afford them succor; indeed, that the arrival of Reenforcements would only aggravate their difficulties.

At this time, Major-General Burnside was in command of the Department of the Ohio, which included Eastern Tennessee and Kentucky. Early in August,