Nevertheless, Thomas placed his forces at Rossville Gap and along Missionary Ridge in preparation against further attacks. The morning of the 21st found the Union Army of the Cumberland more or less reorganized. With the exception of some skirmishing, the Union forces were not molested. The losses on both sides were appalling and the percentages surprisingly equal. The following tabulation of casualties at the Battle of Chickamauga is based on Thomas L. Livermore’s _Numbers and Losses in the Civil War in America, 1861-65_: Army Total Total Killed Wounded Missing Percent Strength Casualties Casualties Union 58,222 16,170 1,657 9,756 4,757 28 Confederate 66,326 18,454 2,312 14,674 1,468 28 _The Siege of Chattanooga_ Thomas remained in position at Rossville throughout the 21st, but it was evident that the Confederates could turn his right flank and cut him off from Chattanooga. He suggested to Rosecrans that the Union Army concentrate at Chattanooga. In anticipation of receiving an order to withdraw to the town, Thomas instructed his officers to prepare their commands for the movement. Rosecrans adopted the suggestion and that evening Thomas withdrew the Union forces to Chattanooga. All wagons, ambulances, and surplus artillery had already departed for Chattanooga during the day. By morning of September 22, all Union troops were in position in the town. [Illustration: _Wartime view. Lee and Gordon’s Mills, Chickamauga Battlefield._ Courtesy National Archives.] The situation in which the men in blue found themselves in Chattanooga was not pleasant. The Tennessee River walled them in on the north, although a pontoon bridge and two ferries offered escape possibilities. Lookout Mountain blocked the way on the west, and Missionary Ridge to the east and south, now held by the Confederates, completed the circle. [Illustration: _Wartime view of Chattanooga in 1863—Lookout Mountain in distance._ Courtesy National Archives.] Bragg issued orders for the pursuit of the Army of the Cumberland, then countermanded them. Instead, the Confederate troops began to take up siege positions around Chattanooga. In these positions the Confederates dominated the Union lines. Bragg’s men controlled all the railroads leading into the town; Confederate batteries and sharpshooters commanded the Tennessee River, and river traffic ceased; they controlled the roads on the south side of the river and kept under fire the one road north of the river leading to Bridgeport, the nearest Union supply base. Only the road over Walden’s Ridge and down through the Sequatchie Valley to Bridgeport was open to General Rosecrans. [Illustration: _Maj. Gen. Ulysses S. Grant._ Courtesy National Archives.] [Illustration: _Maj. Gen. William T. Sherman._ Courtesy National Archives.]