Papers of the American philanthropist and collector. Her first husband was financier Collis P. Huntington; her second husband, Henry E. Huntington. Correspondence (1892-1923); inventories of paintings, jewelry, and real estate; bills and receipts from art dealers, galleries and stores, including Joseph Duveen, J. Seligmann, and Tiffany & Co.

Henry Clay Frick (1849-1919), a Pittsburgh industrialist who made his fortune in coke and steel, was also a prominent art collector. This series consists largely of Frick's incoming correspondence, with some outgoing letters, on matters relating to business and investments, art collecting, political activities, real estate, philanthropy, and family matters.