The 8th Indiana Volunteer Infantry was organized at Indianapolis, Indiana, on April 21, 1861, for a three-month enlistment. On June 19, 1861, the regiment was moved to Clarksburg, West Virginia, and attached to William Rosecrans' Brigade, in George B. McClellan's Provisional Army of West Virginia. On June 29, it was marched to Buckhannon, West Virginia, and occupied Buckhannon on June 30. The regiment engaged in the Western Virginia Campaign, July 6–17, fighting in the Battle of Rich Mountain on July 11. The regiment was mustered out of service on August 6, 1861.