Commonwealth Communities - Listing of all counties with respective towns. - http://www.mass.gov/?pageID=mg2subtopic&L=4&L0=Home&L1=State+Government&L2=County+Government&L3=Counties&sid=massgov2
Massachusetts Profiles - Population, demographic and housing information for each county, from the U.S. Census Bureau. - http://quickfacts.census.gov/qfd/states/25000.html