3rd Massachusetts Heavy Artillery Regiment

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. Attached to 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