Cumberland County is a coastal county located on the Delaware Bay in the Southern Shore Region of the U.S. state of New Jersey. As of the 2020 census, the county was the state's 16th-most-populous county, with a population of 154,152, a decrease of 2,746 from the 2010 census count of 156,898. Its county seat is Bridgeton. Cumberland County is named for Prince William, Duke of Cumberland. The county was formally created from portions of Salem County on January 19, 1748.