The Hall Family Collection consists of volumes, papers, photographs, and objects created or owned by the pre-eminent United States Naval Observatory (USNO) scientists, Asaph Hall III (1829-1907), Asaph Hall IV (1859-1930), their families, and descendants. The collection is relatively brief in scope, but contains rich and varied sources of professional and personal information for the Hall family over multiple generations. Among the paper materials, highlights include genealogical research tracing Hall family ancestors to the 17th century, personal narratives of family history, correspondence, and published material about the Halls, and correspondence and blueprints from renown telescope maker Alvan Clark. Photographs include both studio and personal photographs, and represent Hall family members, professional associates, and places associated with the Hall family, dating from the mid-19th century through the late 20th century. Objects comprise the smallest part of the collection, but add a compelling personal dimension to the paper and photographic materials- items include dresses worn by Katherine and Mary Hall as youths, earrings made from a lock of Moses Cockrell's hair, and objets d'art from the heirloom 18th century secretary that currently stands in the USNO Library., While the bulk of this collection involves members of the Hall family, some unrelated but prominent names are represented in smaller quantity. Such individuals include Dwight D. Eisenhower (1890-1969), former U.S. President and President of Columbia University; Charles Elmer (1872-1954), astronomer and co-founder of Perkin-Elmer optical company; Caroline Furness (1869-1936), astronomer and professor at Vassar College.