Notes and maps from an unfinished project to map the turnpike and plank road networks of the states from New York to Virginia/West Virginia down to 1860 and for two completed journal articles on the turnpikes and plank roads of New York State during the same period.

The Delaware Coach Company was originally incorporated as the Wilmington & Philadelphia Traction Company on June 25, 1910, and operated an electric street railway line from Wilmington, Delaware, to Chester, Pennsylvania, and to Philadelphia. Throughout the early twentieth century, the company purchased stock in and leased numerous electric railway, transportation, and utilities companies in the Wilmington and Chester areas. In 1941, it changed its name to the Delaware Coach Company as trackless trolleys and buses replaced electric streetcars. Included are official documents and correspondence; personnel and financial records; public relations files; land deeds; legislation; labor agreements and contracts; equipment, fare, and route policies; ordinances; minute books, and other miscellaneous material created by Delaware Coach and its predecessor electric streetcar companies.

The Manheim, Petersburg and Lancaster Turnpike or Plank Road Company constructed a plank road between the named towns in 1851 to 1852, during the plank road craze. The records consist of eight pocket volumes and some loose papers kept by the company treasurer, such as a subscription book, toll gatherers' receipt book, and payment book.

Pierre Samuel "P.S." du Pont (1870-1954) was an industrialist, entrepreneur, and philanthropist. He was president of E.I. du Pont de Nemours & Company from 1915 to 1919 and chairman of the board of directors from 1919 to 1940. P.S. du Pont was the great-grandson of Eleuthère Irénée 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). During the early 1920s, P.S. du Pont became an active collector of Du Pont materials, and bought several important bodies of manuscripts from French dealers. This collection consists of manuscripts he collected that are primarily concerned with Du Pont de Nemours, the Physiocrats, the French Revolution, and the antecedents of the Du Ponts and allied families in France. The collection also contains the Wilmington & Kennett Turnpike Co. records dating from 1811 to 1921 that were acquired by P.S. du Pont from 1919 to 1920 when he purchased the company's stock, widened the road, and turned over its administration to the Delaware State Highway Department.