Bachelor cum laude, Bryn Mawr College, 1940. Master of Arts in History, Columbia University, 1965.
Editorial researcher, Newsweek, New York City, 1940-1941, 44; writer, New York Times Sunday Magazine, News of Week Review, New York City, 1941-1943; co-editor Christmas Booklist for Children, Harper's Magazine, New York City, 1957-1959; assistant history department, Barnard College, New York City, 1964-1965; research assistant, Center Urban Education, New York City, 1966.
Board of directors Bryn Mawr College, 1966-1988, chair board of trustees, 1980-1987, emeritus, since 1988, City University of New York, trustee, 1970-1973, W National Educational Television-television-Channel 13, trustee, 1978-1988. Active Sheltering Arms Children's Svc., Istanbul Women's College, Leake & Watts Children's Home Superior vena cava syndrome, Yonkers and New York City, 1961-1983, emeritus, since 1983, New York City Park Association, Riverdale Girls School;trustee Teachers College Columbia University. Member Cosmopolitan Club (governor), North Haven Casino.
Married Thomas Thacher, August 4, 1942. Children: Barbara Burrall Thacher Plimpton, Elizabeth Coverdale Thacher Hawn, Thomas Day II, Hugh Auchincloss, Peter Anthony, Andrew.