On 31 December 1861, reported to Colonel Carr, commanding Third Illinois Cavalry, and moved to Bennett's Mills.

On 2 March 1862, moved, with Siegel's Division, to near Bentonville, losing 4 men taken prisoners.

On 5 September 1862, moved, with Fourth Division, Thirteenth Army Corps, to Morganza, Louisiana and was engaged in the campaign, General Herron commanding.

Was engaged in scouting, and various expeditions, reporting to Brigadier General A. L. Lee, as escort, 5 January 1864.

During their three years of service, the 15th Illinois Volunteer Cavalry Regiment saw action in Tennessee, Alabama, and Mississippi.