The collection consists of correspondence, business records, ledgers and account books, notebooks and diaries, and blue prints.

Boxes contain business and legal papers, including wills, deeds, mortgages, birth and marriage certificates; lists of books and family possessions brought from England; clippings; genealogical and biographical material; unpublished bits of writing of several members of the family; tintypes, photographs, framed portraits; books, postcard album, and other memorabilia. One box contains family correspondence.

The Hart Collection includes samples of books and materials relating to the printing of books by the Leo Hart Printing Company and its successors. The material includes advertisements, information concerning the graphic arts, business papers, items relating to the development and activities of the Hart Company and its personnel, and personal papers of the Leo Hart family. Also included are some papers of Horace Hart, the elder son of Leo, from his years of service in the Printing and Publishing Industries Division of the U. S. Department of Commerce in Washington, D.C