This regiment was organized at Lafayette in May. 1861, for state service, and was reorganized for U. S. service in June, for three years. It was mustered in June 14, left the state July 1, for Clarksburg, W. Va., then marched to Rich mountain, which was reached during the progress of the battle on the 11th, and joined in the pursuit of the enemy, capturing many prisoners. It was stationed in Elk Water valley until Nov. 19, being engaged in the repulse of Lee’s forces, and at the battle of Green Brier river. The original strength of the 15th was 1,056.