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.
Collection consists of personal, legal, and business-related letters and documents concerning the life and affairs of J. Houston Mifflin. Also, similar documents to, from, and about other members of the extended Houston and Mifflin families. Contains typed copies of two letters from J. Houston Mifflin to his son, Lloyd Mifflin, containing an eye-witness account of the June 1863 Confederate advance into Wrightsville. Also, a legal document signed by John Passmore.