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 95 acres (380,000 m2),[5] two years after he and his family left France to escape the French Revolution.

The mill became the largest manufacturer of explosive black powder in the U.S.[11] E. I. du Pont's wife and three children joined him in July 1802, and by 1803, the residence was complete.

[12] As he travelled frequently for business affairs, his eldest son Albert Victor became responsible for managing the running of the mills in his absence.

Pierre S. du Pont (1870–1954), who was president of DuPont from 1915 to 1919, and chairman of the board when the mill closed, founded what is today Longwood Gardens.

Those in the household performed mainly domestic duties, and those employed after the end of slavery and indentured servitude were often family members of those working in the powder mills.

Some of these workers' communities included private family homes, small villages of dwellings, and larger facilities that rented living spaces to employees.

The Upper Banks referred to the original powder yards, the main du Pont residence, and workers' communities upstream along the Brandywine.

The communities and villages developed within and near Eleutherian Mills also provided taverns, general stores, schools, post offices, and more.

[15] After the introduction of smokeless powder, the mills were to be closed in the 1910s but were kept open at the request of the federal government until after the end of World War I.

[4] In 1952, family members donated 185 acres (0.75 km2) of land and the DuPont company established a $6,000,000 endowment for the Eleutherian Mill-Hagley Foundation for a museum of industrial history.

Alfred Victor du Pont acquired additional property downstream from the Eleutherian Mills to add to the manufacturing site.

Stables, offices, a machine shop, and a steam powerhouse from the late 19th century also were located in the complex, as was a narrow gauge railway.