Gloucester County (/ˈɡlɒstər/) is a county in the U.S. state of New Jersey. As of the 2020 census, the county was the state's 14th-most populous county with a population of 302,294, its highest decennial count ever and an increase of 14,006 (+4.9%) from the 288,288 counted in the 2010 census, which in turn represented an increase of 33,615 (+13.2%) from the 2000 census population of 254,673. Its county seat is Woodbury.