Mary Williamson Averell Harriman (July 22, 1851 – November 7, 1932) was an American philanthropist and the wife of railroad executive E. H. Harriman. Born in New York to a successful family, Averell married Harriman in 1879. Averell's father introduced Harriman to the railroad business. After Harriman's death, his wife was left with between $70 and $100 million. She became dedicated to philanthropy, donating the land that became Harriman State Park and largely funding the development of the controversial Eugenics Record Office. Averell had several children; her son, W. Averell Harriman became governor of New York and her daughter Mary Harriman Rumsey founded the Junior League.