Sewell is an unincorporated community within Mantua Township in Gloucester County, New Jersey, United States. It is named for United States Senator William Joyce Sewell.Sewell is served as United States Postal Service ZIP code 08080. As of the 2010 United States Census, the population for ZIP Code Tabulation Area 08080 was 37,433.Sewell is notable for containing the Inversand marl pit, the last operational greensand mine in the world. The location has become renowned for its paleontology and is similar to many of the sites studied by early paleontologists, particularly Edward Drinker Cope. It is also home to the Barnsboro Inn, the oldest bar in New Jersey.Sewell is also home to Rowan College at Gloucester County and the Gloucester County Institute of Technology, both located within Deptford Township. The community is a planned stop on the Glassboro–Camden Line, a proposed 18-mile diesel multiple unit light rail line.