The Second Delaware Infantry was organized in Wilmington between June and October 1861. The Second was attached to the Army of the Potomac and participated in all its major engagements. Because the Second performed so well in the retreat at Fredricksburg, the regiment became known by other units as the "Crazy Delawares" who "would hardly obey an order for retreat." The Second was mustered out at the expiration of its enlistment on July 1, 1864.