Horace Holden Thayer, Jr. (1878-1959) was a naval architect, mechinical engineer, and businessman. Between 1909 and 1914 Thayer worked for the Delaware Construction Company which was a building company, constructing residential homes in downtown Wilmington, Delaware. This collection contains photographs of fifteen homes taken between 1910 and 1914. The images are of exterior views only.

Pierre S. du Pont incorporated the Delaware School Auxiliary Association in 1919 to finance the construction of new school buildings throughout Delaware. Between 1918 and 1940 he donated $5,000,000 to build some 120 schools. This collection contains photographs, almost all exterior, of 114 public elementary and secondary schools in Delaware.

The DuPont Company purchased a site near City Point, Virginia on the James River in 1912 in order to build a dynamite plant located closer to the southern market. The panoramic photographs show exteriors of the plant, views of the workers' housing, the town (including the African American section), and a photograph of the Hopewell China Corporation, a post-war reuse of one of the facilities.

The Woodlawn Trustees, Incorporated, is a non-profit real estate development firm incorporated in Delaware on December 12, 1918, by textile manufacturer William Poole Bancroft (1835-1928). Their records include charters, minutes, officer lists, directors' correspondence, real estate records, property maps, reports, drawings and specifications and newspaper and journal articles on the history of the Trustees and of the Bancroft family.