From 1802 to 1921, Eleutherian Mills was a gunpowder mill site used for the manufacture of explosives founded by Eleuthère Irénée du Pont, which grew into the DuPont company. The name also refers to the house on the hill above the mills, which was the first du Pont family home in America. In 1957 the site became an outdoor museum when the Hagley Museum and Library was founded. The site was declared a National Historic Landmark in 1966. History Jacob Broom built a cotton mill on the Brandywine Creek just north of Wilmington, Delaware, in 1795, which burned down in 1797. In 1802, he sold the site, complete with a working dam and mill race, to Eleuthère Irénée du Pont, who paid $6,740 for the , two years after he and his family left France to escape the French Revolution. He set up the Eleutherian gunpowder mill, based on gunpowder machinery bought from France and site plans for a gunpowder mill supplied by the French government. He also built housing for 30 workers. Starting initially by reworking damaged gunpowder and refining saltpetre for the U.S. government, he quickly moved into gunpowder manufacture. Saltpetre was refined in an area between the house and the mills that now is occupied by a formal garden. Charcoal was produced from the willow trees that lined the Brandywine. The first domestic supplies of high-quality gunpowder in the U.S. were made here. By the end of 1804, DuPont had sold 39,000 pounds of powder; the following year, sales tripled. The federal government and John Jacob Astor's American Fur Company became regular customers. In 1813, the Hagley property, just downstream from the original mills, was purchased, doubling the size and capacity of the mills. Sales grew during the Mexican–American War and the Crimean War. During the American Civil War, the firm sold 4 million barrels of powder to the federal government. The mill became the largest manufacturer of explosive black powder in the U.S. Role of the du Ponts E. I. du Pont's wife and three children joined him in July 1802, and by 1803, the residence was complete. Their home served as a center of business and social life at Eleutherian Mills for years to come. As he travelled frequently for business affairs, his eldest son Albert Victor became responsible for managing the running of the mills in his absence. Members of the du Pont family