The Blackwood mss., 1852-1887, consists of letters to Sir Stevenson Arthur Blackwood, 1832-1893, postal official and reformer, and to his mother, Cecilia Georgiana Byng Blackwood, 1802-1881.
The Mill mss., 1852-1869, are letters from John Stuart Mill, 1806-1873, philosopher and economist, to John Chapman, 1822-1894, publisher, editor, and physician.
The Eigenmann mss., 1851-1971, consists of the papers of Carl H. Eigenmann, 1863-1927, ichthyologist, and his wife, Rosa Smith Eigenmann, 1858-1947, ichthyologist.
The Merrill family mss., ca. 1851-1927, consist of correspondence, diaries, photographs, and writings of various members of the George Merrill family of New York. Present are papers of George Merrill, 1832-1888, his wife Emma Fitzrandolph (Laing) Merrill, their sons William Laing Merrill and George Grenville Merrill, and George's wife Pauline (Dresser) Merrill.
The Hill mss., 1851-1914, consist mainly of letters and papers of James Nathaniel Hill, 1833-1902, farmer of Owen County, Indiana, and Civil War soldier.
The New Jerusalem Church (Illinois) mss., 1851-1903, are records of the Illinois association of the New Jerusalem Church and the New Church of Peoria, Illinois.