Gibbstown, New Jersey. Gibbstown is a unincorporated community and census-designated place (CDP) located within Greenwich Township, in Gloucester County, New Jersey, United States. As of the 2010 United States Census, the CDP's population was 3,739. Gibbstown is the location of C. A. Nothnagle Log House, purportedly the oldest house in New Jersey and the oldest surviving log house in the U.S., dating to around 1638.