The Mary Lyon Collection consists of letters by and to educator Mary Lyon, her published and unpublished writings, biographical information about her and memorabilia associated with her, books that were in her personal library, materials about the Lyon family and the Massachusetts towns closely associated with her early life, and portraits and other likenesses of her. The collection primarily documents Lyon's activities as a pioneering educator of women and her work as the founder and first principal of Mount Holyoke Female Seminary. Correspondence (1818-1849, n.d.) contains letters by and to relatives, friends, and colleagues concerning her work, particularly at Mount Holyoke, and aspects of her personal life. Correspondents include educators Zilpah Grant Banister and Eunice C. Cowles, L.T. Guilford, and other Mount Holyoke graduates, Lyon's niece, Abigail Moore Burgess, missionary Justin Perkins, and Laban and Elizabeth Wheaton, founders of Wheaton Female Seminary. Writings (circa 1827-1849, n.d.) include pamphlets that Lyon wrote to publicize Mount Holyoke, the Missionary Offering (1843) which reflects her support of missionary work, and many unpublished documents such as her student compositions, her notes for lectures, and her journal describing travels in Pennsylvania, New York State, and Michigan in 1833. Notes on Lyon's Remarks (circa 1837-1849) were compiled by Mount Holyoke students and teachers and reflect her views about religion, the purpose of education, character, and other subjects. Biographical Material and Memorabilia (circa 1778-) consists of articles, newspaper clippings, and papers about Lyon's life, jewelry, textiles, and other items that belonged to her and others, and items once used to furnish the Mary Lyon Room at Mount Holyoke. These materials include information about the many posthumous honors conferred upon her. Lyon's Library (1809-1847) consists of books that she owned and includes writings by Catharine Esther Beecher, Amos Eaton, Edward Hitchcock, and John Milton. Lyon Family materials (circa 1836-) chiefly consist of published and unpublished genealogies about various branches of the family both in the United States and Europe. There is also a photograph album that appears to contain portraits of Lyon's brother, Aaron E. Lyon, and his relatives. Places Associated with Lyon (circa 1849-) consists of publications, notes, postcards, and photographs concerning Ashfield, Buckland, and Byfield, Massachusetts. Portraits and Other Likenesses (1832-) contains prints of a daguerreotype, a ferrotype, and paintings of Lyon taken or completed during her lifetime as well as later paintings and drawings of her. Lyon's correspondence and writings were microfilmed in 1987 and the collection includes four sets of the film and related user guides. Oversize (Folio) Material (circa 1827-) in the collection is boxed separately.