Five generations of du Ponts lived in this house. E. I. du Pont built the stuccoed, Federal-style stone edifice with pedimented, fanlit doorway on a bluff above the Upper Yard, so he could keep an eye on the operations. Pierre Samuel du Pont de Nemours illustrated the floorplan in a letter to his wife in France in 1815. Drawings survive that show family activities in the house and on a two-story Ionic piazza at rear. The Marquis de Lafayette stayed here during his American tour. “Boss Henry” du Pont enlarged the house; his son, Henry Algernon du Pont, grew up here and sketched the dwelling and grounds (1852). An explosion in the yards severely damaged the place in 1890, after which it was refurbished as a workers' clubhouse. Henry Algernon's daughter Louise (Mrs. Francis B. Crowninshield) took over the property following the closing of the powder works in 1921 and undertook a restoration with a leading Philadelphia firm. The interior was substantially rebuilt and a lovely spiral stair was brought in. A founder of the National Trust for Historic Preservation, Crowninshield helped restore the Virginia house, Kenmore, in the 1930s, and Independence Hall and Society Hill, Philadelphia, in the 1950s (plus the Dutch House, NC7). Her Eleutherian Mills interiors can be compared to those of her brother, Henry Francis du Pont of Winterthur (CH10). Upon her death in 1958, the Eleutherian Mills–Hagley Foundation undertook further restoration, which First Lady Jacqueline Kennedy came to see in 1961 as she worked with Henry Francis getting ideas for redecorating the White House. Eleutherian Mills opened to the public three years later. Models on display show the development of the house, which underwent refurbishment in 2004–2005.