The documents include Mitchell's commissions as lieutenant and captain, discharge papers, muster rolls, a list of missing military property, ordnance returns, and an affidavit relating to the pension of John N. Fox, a veteran of Company D., 1st Vermont Cavalry. Also included in the collection is a letter from the Malden, Massachusetts G.A.R. post and Mitchell's obituary.

Harris B. Mitchell was born in March, 1839 in Kennebunk, Maine. As a young boy his family moved to New Hampshire and then to Newbury, Vermont, where he was a farmer. He enlisted in Co. D, 1st Vermont Cavalry as a sergeant on September 28, 1861. He was promoted to first sergeant of Co. D and then to second lieutenant in Co. I on March 22, 1864. He was promoted to captain of Co. A on November 19, 1864. He was transferred to Co. B June 21, 1865, and mustered out August 9, 1865. After the war he moved to Malden, Massachusetts, where he eventually became the police chief. He moved to Boston in August, 1912, where he died on January 5, 1913.