Newtonville is an unincorporated community and census-designated place (CDP) in Buena Vista Township in Atlantic County, in the U.S. state of New Jersey. As of the 2020 census, Newtonville had a population of 742. Newtonville is located on a Conrail line 4.7 miles (7.6 km) east-northeast of Buena. Newtonville has a post office with ZIP Code 08346.