2pp., 7 3/4 x 9 3/4 in., creased, some separation at creases, soiling to edges, on "Head Quarters of the Army" letterhead.  

General Halleck notifies Major General Rosecrans of communications from General Burnside at Cumberland Gap: "...he holds all East Tennessee above London & also the gaps of the North Carolina Mountains. A cavalry force is moving towards Athens to connect with you." The message continues, "After holding the mountain passes on the west & Dalton or some other points on the R. Road to prevent the return of Bragg's army, it will be decided whether your army shall move further south into Georgia & Alabama. It is reported here by deserters that a part of Bragg's army is reenforcing (sic) Lee. It is important that the truth of this should be ascertained as early as possible. / (sgd) H.W. Halleck. Genl in Chf. / Telegram (Official Copy) D.C. Wager. A.A.G" 

Over the next few days, General Rosecrans worked to concentrate his forces, and on 17 September, moved his troops to protect roads to Chattanooga against Bragg's forces. The resulting Battle of Chickamauga got underway on 19 September and lasted through the next day, when Confederate General Longstreet drove two divisions of Federal troops away and causing Rosecrans, McCook, and Crittenden to retreat toward Chattanooga. Only Union General Thomas J. Wood remained to fend off desperate assaults on his position on Snodgrass Hill, which he did until finally being ordered to withdraw toward Rossville, eventually retiring to Chattanooga. Though the battle at Chickamauga ended in a tactical Confederate victory, the contested city of Chattanooga would be under Union control in about two months' time.