Gabriel Manigault (1758-1809) was a Charleston merchant, plantation owner, architect, and South Carolina state Representative. In 1805, Manigault sold part of his property in South Carolina and moved to Clifton, an estate near Philadelphia, Pennsylvania. These are copies of Manigault's letters relating to members of the du Pont family.

Gertrude Ruhnka (1891-1981) was a research librarian at the Huntington Library in California. The collection contains her unpublished manuscript, "Love for life: a self-portrait of the first three generations of du Ponts in America, 1791-1834," and two letters from Ruhnka to J.B. Lippincott Company and Dr. Walter J. Heacock of the Eleutherian Mills-Hagley Foundation.

Pierre Samuel du Pont de Nemours (1739-1817) was a French political economist, writer, publisher, and public administrator. Victor Marie du Pont (1767-1827), the son of Pierre Samuel, was a French diplomat who later immigrated to the United States and established various trading companies before moving to Delaware. This collection contains three photocopied documents in French: a memoir by du Pont de Nemours, letter of Eustache Briux to Charles Maurice de Talleyrand-Perigord, and a letter from Victor du Pont to Talleyrand.

Pierre Samuel du Pont de Nemours (1739-1817) was a French political economist, writer, publisher, and public administrator. Louis Marie de La Revelliere-Lepeaux (1753-1824) was a member of the French government in the time surrounding the French Revolution, including the Estates-General, the National Convention, and the French Directory. The letter from du Pont to La Revelliere-Lepeaux concern's du Pont's son Victor, who was then serving as French consul at Charleston, South Carolina.