Carya washingtonensis was described from three type specimens, the holotype, number "HU60073A", and two paratypes, numbers "HU60073B" and "IU5343". Both the holotype and one paratype are preserved in the paleobotanical collections housed at the Harvard University Biology Laboratories. The second paratype is deposited in the paleobotanical collections in the Indiana university, Department of Geology.
