Correspondence, manuscripts of poems, and manuscripts of lectures by Benjamin. The correspondence consists of original letters of Benjamin, typescript and photostatic copies of Benjamin letters in other libraries, and letters to Benjamin from some of his literary contemporaries including Paul Hamilton Hayne, Willis Gaylord Clark, John Lothrop Motley, and Fitz-Greene Halleck. Many of the letters relate to Park Benjamin's lecture tours. There are other family letters and many documents relating to the Benjamin family,and two letterbooks of John Lothrop Motley. Also, a large amount of genealogical material of the Benjamin family, and its related families from the 16th century to the present day. There are also financial records, monographs, clippings, and photographs.

Correspondence, manuscripts, documents, photographs, memorabilia and printed materials of John Mitchel, John Purroy Mitchel, and other members of the Mitchel and Purroy families. The collection concerns Irish nationalism, family matters, Purroy family business interests in Central America, the John Purroy Mitchel Memorial and William Brown Meloney's files relating to his research and writing of "The Story of John Purroy Mitchel" along with the manuscript and typescript drafts for this unpublished biography.

Correspondence, manuscripts, typescripts, contracts, legal briefs, patents, and other documents, music scores, cartoons, technical drawings, account books, blueprints, photographs, clippings, printed legal briefs & transcripts, proofs, scrapbooks, and other printed materials of William M. Speer.