The Seventh Rhode Island Volunteers was mustered into the service of the United States to serve for three years on September 6, 1862. They also drew Enfield rifle-muskets on this day. In addition the Seventh was clothed in the full uniform of the United States Army; a feature of their coats being a very high collar. On September 10, the regiment left Rhode Island and proceeded to Camp Casey outside of Washington, D.C. Here they remained for several weeks before joining the First Brigade, Second Division, Ninth Corps on October 6, encamped outside Sharpsburg, Maryland following the victory at Antietam a month earlier. The Seventh remained encamped at Pleasant Valley, Maryland, for three weeks, perfecting its drill, while losing several members of the regiment to disease and the elements.