David Harris Underhill was an American librarian and author. He was a librarian for the St. John's Methodist Episcopal Church in Williamsburgh and the Astor Library. He was librarian in charge of the newspaper room at the New York Public Library. Underhill helped to organize the Underhill Society of America in 1892, and served as Secretary and Family Historian until his death in 1936. He was also an active author, editor, and compiler with several published works to his credit.