Correspondence, speeches, military reports, accounts of engagements of the Army of the Potomac, record books, biographical notes, and other material pertaining primarily to the Civil War. Contains Chamberlain's account of the Battle of Gettysburg, 1863; reports of Company G, 20th Maine Infantry Regiment; and correspondence relating to the state militia, military reunions, and data for a history of the 5th U.S. Army Corps. Correspondents include John Marshall Brown, Henry S. Burrage, Selden Connor, Charles Hamlin, O.O. Howard, Carswell McClellan, Horace Binney Sargent, William Henry Seward, Gouverneur Kemble Warren, and Cyrus Woodman.