Lyon, Mary, 1797-1849, American educator, founder of Mt. Holyoke College, b. Buckland, Mass. She attended three academies in Massachusetts; later she taught at Ashfield, Mass., Londonderry, N.H., and Ipswich, Mass. Interested in promoting the higher education of women, she won the aid of several influential men and succeeded (1837) in establishing Mt. Holyoke Female Seminary (later Mt. Holyoke College) at South Hadley, Mass. She served as principal for 12 years, directing the development of a well-rounded college program and emphasizing the principle of service to others.