The Averell Family Papers consist primarily of the personal, business, and legal papers of William Holt Averell of Cooperstown, New York. The collection also includes a substantial number of papers relating to or written by James Averell, Jr., William Holt Averell's father. In addition, the collection includes papers relating to other members of the Averell family and genealogical information regarding the Averell, Carter, Slayton, and Waldby families. The date range is mostly from 1790 to 1880.

The Campbell Family Collection, 1790s -1870s, covers four generations and documents the history of the family in Cherry Valley, Otsego County, NY in the earlier part of the nineteenth century. The main focus of the collection is the correspondence of Judge William W. Campbell and his manuscript "Annals of Tryon County." Also included are papers of Cleveland J. Campbell, Helen S. Campbell, Douglas Campbell, William A. Campbell, Henry J. Campbell, Samuel Campbell, Samuel Starkweather, Harriet Bowers Paige Campbell, James S. Campbell, and other family members. Also included an early nineteenth century manuscript music book, survey maps of Cherry Valley and Belvedere, and the correspondence, medical observations, and financial records of William B. Campbell.

Letters, invoices, accounts, and land, legal, and military papers of Jellis/Jelles Fonda of Montgomery County, N.Y. Also contains two ledgers of his general store in Caughnawaga (Fonda), Montogmery County, N.Y. Subjects of note include Fonda's trade with London markets and with Native Americans, many of whom were customers in the ledgers. Includes some photocopies.