During the Chattanooga campaign from 24 September to 23 November 1863, there was a reorganization and McCook's brigade was reassigned as the 3rd Brigade, 2nd Division, XIV Corps, Army of the Cumberland. The 2nd Division was led by Brigadier General Jefferson C. Davis, XIV Corps was under Major General John Palmer, and the army was commanded by Thomas. The 110th Illinois Infantry was added to McCook's brigade to supplement the original four regiments. While camped at Caldwell's Ford, the regiment was subjected to a surprise bombardment by Confederate artillery. This was soon silenced by answering Union artillery fire, but not before the chaplain was killed and other men were wounded. At this time, the regiment numbered about 600 men. Brigadier General William Farrar Smith utilized McCook's brigade to help establish the Cracker Line, which opened up a supply route to beleaguered Chattanooga. Troops from McCook's brigade provided security and helped build a road. Men from the 85th and 86th Illinois served as oarsmen during the expedition. During the Battle of Missionary Ridge on 23 November, Major General William T. Sherman failed to use Davis' division which was at his disposal. Davis' division led the pursuit after the battle, but the Confederates escaped.