Sewell is a census-designated place and unincorporated community within Mantua Township and Washington Township in Gloucester County, in the U.S. state of New Jersey, within the Philadelphia metropolitan area. As of the 2020 United States census, the CDP's population was 3,346. The CDP was named after United States Senator William Joyce Sewell. The community is served as U.S. Postal Service ZIP Code 08080. Sewell is home to Rowan College of South Jersey.