On June 24, 1863, the Army of the Cumberland, including the 1st OVI and William Patterson, began moving toward Tullahoma, Tennessee. On the first day, the Confederate Army was encountered at Liberty Gap, Tennessee, 12 miles from Murfreesboro. The 1st OVI was held in reserve for this engagement, but was under heavy artillery fire.
On June 26, at 8 o’clock in the evening, the regiment was withdrawn from the picket line leaving its camp fires burning and made a night march of five miles through rain and deep mud to Millersburg. It was a difficult march due to constantly falling rain that made the roads nearly impassable from the deep mud and broken-down vehicles.
Finally, on June 29, the regiment arrived at Manchester, Tennessee. At this point, all of the extra baggage of the Army of the Cumberland, including knapsacks of the men, were sent back to Murfreesboro. The regiment moved on passing through Manchester and arriving at Tullahoma at one o’clock at night. When the regiment arrived they found extensive Rebel camps — tents still standing — artillery, artillery shells, and other military material at the depot. On July 2 the artillery shells accidently exploded killing two member of the regiment and wounding several others.
The 1st OVI and the Army of the Cumberland remained at Tullahoma until August 16.