John Mason Clarke was the Director of the New York State Museum from 1904 until his death in 1925. This collection includes correspondence, clippings, and diaries.

The Pruyn Family Papers contains documents relating to three consecutive generations of the John Pruyn Family, along with genealogies and personal papers of more distant family relations. An autograph collection of presidents, statesmen, and local historic figures is included. The ownership of 43-45 North Pearl Street is documented from the first sale in 1679 to the last in 1968. The estates of Eleanor Erving, Justine Bayard Erving and Van Rensselaer Pruyn are also documented.