The General 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, originally constructed in 1750 as a one-and-a-half story brick structure, became a fine example of Georgian architecture with Federal and Greek Revival modifications. In the early 19th century, General John Frelinghuysen added the second floor to the main section. An attorney, he served as a Brigadier General during the War of 1812 and later was the Surrogate of Somerset County.