The 3rd Massachusetts Heavy Artillery Regiment lost 2 enlisted men killed and 1 officer and 38 enlisted men to disease during the Civil War.

1864
August Organized for one year by consolidation of 3rd, 6th, 7th, 8th, 9th, 10th, 11th, 12th, 13th, 14th, 15th and 16th Unattached Companies Heavy Artillery. Assigned┬áto 2nd Brigade, Hardin’s Division, 22nd Army Corps, Dept. of Washington and engaged in garrison duty in the Defenses of Washington north of the Potomac
1865
September 18 Mustered out