 After garrison duty at the United States Naval Academy in Annapolis , Maryland , the regiment served with the Coast Division commanded by Maj. Gen. Ambrose Burnside . The Coast Division was deployed in January 1862 for operations on the coast of North Carolina , and participated in the Battle of Roanoke Island and the Battle of New Bern among other engagements . Burnside 's division was recalled to Virginia in July 1862 . The 21st Massachusetts was then attached to the Army of the Potomac and participated in several of the largest battles of the Civil War , including the Second Battle of Bull Run , the Battle of Antietam , and the Battle of Fredericksburg . The most devastating engagement of the war for the 21st was the Battle of Chantilly , fought on September 1 , 1862 , during which the unit suffered 35 percent casualties . From March 1863 to January 1864 , the 21st served with Burnside in the Department of the Ohio , seeing action in Kentucky and eastern Tennessee . In May 1864 , the regiment rejoined the Army of the Potomac , participating in Lt. Gen. Ulysses Grant 's Overland Campaign and the Siege of Petersburg . The regiment was a favorite of Clara Barton , the famed battlefield nurse , who was also from Worcester County , Massachusetts . 
