Under President Abraham Lincoln's first call for volunteers, 75,000 men were needed for three months service to 'put down the rebellion.' Delaware's quota of this first call for volunteers was 780 men. This was rapidly met by the formation of the First Regiment Delaware Volunteers. It was organized at Wilmington, Del. May 22, 1861 and mustered into Federal Service on May 28, 1861. At that time it had 37 officers and 742 enlisted men. This 90 day unit was mustered out early on August 17, 1861. (Dyer says August 30, 1861).
Attached to Dix's Command and assigned to duty on line of the Philadelphia, Wilmington & Baltimore R. R. at Havre de Grace, Elkton, Perryville, Bush River, Gunpowder, Northeast and Charlestown, guarding road and protecting bridges till August.
The composite roster of this regiment contains 556 names. From the numbers given by Dyer above evidently some 250 names are missing from the National Archives Index.