The collection is comprised mainly of correspondence, mainly between Rittenhouse and his family members, but also correspondence between Rittenhouse and various politicians and men of science. Also included are receipts, broadsides and two genealogies, one of the Rittenhouse family and one of the family of Rittenhouses son-in-law, Jonathan Dickinson Sergeant. The items from the 20th century are memorial materials commemorating various members of the Rittenhouse, Abbot and Sergeant families.