The population count of Plymouth County, MA was 495,407 in 2012. The population count of Worcester County, MA was 799,277 in 2012. The population count of Hillsborough County, NH was 401,101 in 2012. The population count of Rockingham County, NH was 295,872 in 2012.
Population
Population Change
Above charts are based on data from the U.S. Census American Community Survey | ODN Dataset | API -