The John Frelinghuysen House was the homestead of the Frelinghuysen family, long significant in New Jersey history. Its wooden wing was presumably built in the early 18th century and may have been moved to the site by the Middaugh family, who owned the property at that time. The main part of the house was originally constructed in 1750 as a one-and-a-half story brick structure and now stands as a fine example of Georgian architecture with Federal and Greek Revival modifications. Gen. John Frelinghuysen added the second floor to the main section in the early 19th century. An attorney, he served as a Brigadier General during the War of 1812 and later was the Surrogate of Somerset County.