Hetfield House 1 Constitution Plz, Mountainside, NJ07092 The Deacon Andrew Hetfield House is a historic site and community center located on the Watchung Reservation. It is…More owned and operated by the Mountainside Historic Preservation Committee. The Hetfield House contains a wide array of historic items and information. It is also used for a variety of related community events. Visit the website for details on upcoming events.