The Frank R. Diffenderffer Collection contains documents collected by Mr. Diffenderffer. These documents are primarily from the eighteenth and nineteenth centuries and include letters, legal and court papers, indentures, receipts, property and probate records, and financial and military papers. The people and businesses represented include George Ross, Jasper Yeates, A. Herr Smith, Timothy Matlack, Mount Hope Furnace, and the Lancaster, Elizabethtown & Middletown Turnpike Road Company.
This collection contains documents beginning with the American Revolution and continuing through the War of 1812, Mexican War, Civil War, World War I, World War II, and the Korean War. There are account books, notes and written letters, vouchers, inspections of camps, receipts of payments, honorable discharge certificates, lists of absentees, envelopes used during the Civil War, and lists of unpaid fines during the service of the Pennsylvania Militia soldiers. There are also newsletters and articles relating to World Wars I and II and the Korean War for advertisement and description of items including the history of the Philadelphia Naval Base.