The regiment remained at Blue Springs until April, then it moved forward with the army of General George Henry-Thomas in the bitter campaign against Atlanta. The regiment participated in all of the skirmishes and battles which occurred up to the Union occupation of Atlanta, which in part included: Lookout Mountain, Missionary Ridge, Tunnel Hill, Rocky Face Ridge, Resaca, Pine Mountain, and Marietta.

After the mustering out of the non-veterans, while the regiment was in Atlanta, the recruits and veterans were consolidated into a Residuary Battalion of seven companies. This was by the order of General Thomas J. Wood, on December 3rd, 1864. The battalion was then placed in command of Lieutenant Colonel Henry W. Lawton. It moved northward with the Fourth Corps to Nashville, there it participated in the battle fought against General John Bell Hood's forces on the 15th of December. The Federals were very successful in all areas of that battle, capturing a large amount of Confederate artillery and many prisoners. Subsequently, the Thirtieth participated in the pursuit of the enemy to Huntsville, Alabama, then onward with the Fourth Corps into eastern Tennessee. The battalion returned to Nashville remaining there until June 1865, when it was transferred to Texas with the Fourth Corps.

By the orders of General Philip Henry Sheridan, on the 12th of July, the company of the Residuary Battalion of the 36th Regiment commanded by Captain John P. Swisher was trans-ferred to The Residuary Battalion of the 30th Regiment, and made Company 'H".

The Thirtieth made many long marches while in Texas, but was not otherwise engaged, and in October 1865 it was still on duty as part of General Sheridan's army of occupation in that state.