Consists of the family papers of former DuPont CEO Lammot du Pont Copeland (1905-1983) and his wife Pamela Cunningham Copeland (1906-2001). The Copelands' papers document the lives and interests of a wealthy American couple in the twentieth century. In particular, the papers of Pamela C. Copeland are an important source of information about the public activities of women in the areas of historic preservation, gardening and horticulture, and philanthropy.

Éleuthère Irénée du Pont de Nemours (1771–1834) was a French American chemist and industrialist who founded the gunpowder manufacturer, E.I. du Pont de Nemours and Company. E.I. du Pont married Sophie Dalmas du Pont (1775-1828) in 1791, and the couple had eight children, one of whom died in infancy. This collection primarily consists of E.I. du Pont's personal and business correspondence; writings and notes; school materials; memoranda on manufactures and tariffs; legal agreements; patents; and land surveys. Also included are Sophie Dalmas du Pont's correspondence and household account records.

Guyencourt Nurseries, Inc. was a Delaware landscape nurser set up by three young horticulturists, William E. and Mary N.R. Phelps and G. Guy Nearing, in 1929. This small group of papers traces six years of depression-era activities by a small Delaware land-scape nursery.

Pierre Samuel "P.S." du Pont (1870-1954) was an industrialist, entrepreneur, and philanthropist. He was president of E.I. du Pont de Nemours & Co. from 1915 to 1919 and chairman of the board from 1919 to 1940. P.S. du Pont was the great grandson of Eleuthere Irenee du Pont (1771-1834), founder of E.I. du Pont de Nemours & Company, and the great-great-grandson and namesake of the French economist, Pierre Samuel du Pont de Nemours (1739-1817). du Pont's personal life is well documented by the photographic collection he left, and it followed certain themes. The greatest of these may be horticultural interests which developed during his creation of the celebrated Longwood Gardens in Kennett Square, Pennsylvania, where he lived. du Pont made many foreign and domestic journeys and recorded his travels. His large extended family is included in this collection. This collection is organized into seven series: Longwood Gardens; Individuals and families; Groups and organizations; E.I. du Pont de Nemours & Company; Trips and vacations; Places; and Culture, society, and service.

Walt Biddle (1925-1995) was a gardener in the household of Louise du Pont Crowninshield (1877-1958) and Francis B. Crowninshield (1869-1950) at Eleutherian Mills in Greenville, Delaware. In his oral history interview transcript, Biddle describes the Crowninshields and life at Eleutherian Mills in the 1940s and 1950s.