The Du Pont family is an American family descended from Pierre Samuel du Pont de Nemours (1739–1817). Since the 19th century the Du Pont family has been one of the richest families in America. Many former Du Pont family estates have been opened to the public as museums, gardens, or parks, such as Nemours Mansion and Gardens, Longwood Gardens, and Winterthur Museum, Garden and Library. The family's first American estate, located at Hagley Museum and Library, has been designated a National Historic Landmark. In recent years, the family has continued to be known for its association with political and business ventures, as well as philanthropic efforts on behalf of various organizations such as The Jockey Club, the Philadelphia Orchestra, the Delaware Art Museum, and the Grand Opera House.