The population count of Essex County, MA was 739,505 in 2011. The population count of Plymouth County, MA was 492,934 in 2011. The population count of Hillsborough County, NH was 400,243 in 2011. The population count of Rockingham County, NH was 295,162 in 2011.
Population
Population Change
Above charts are based on data from the U.S. Census American Community Survey | ODN Dataset | API -