claim: Watertown, Massachusetts is the county seat of Middlesex County.
evidence: Middlesex County is a county in the Commonwealth of Massachusetts , in the United States .. county. County ( United States ). Commonwealth. Commonwealth ( U.S. state ). Massachusetts. Massachusetts. United States. United States. As of 2014 , the estimated population was 1,570,315 , making it the twenty-third most populous county in the United States , and the most populous county in both Massachusetts and New England .. county. County ( United States ). Massachusetts. Massachusetts. United States. United States. population. population. twenty-third most populous county. County statistics of the United States. New England. New England. For administrative purposes the county held two regions , Middlesex-North with its county seat in Lowell , and Middlesex-South with its county seat in Cambridge .. Lowell. Lowell, Massachusetts. Cambridge. Cambridge, Massachusetts. county. County ( United States ). county seat. county seat. Middlesex County is included in the Boston -- Cambridge -- Newton , MA -- NH Metropolitan Statistical Area .. Cambridge. Cambridge, Massachusetts. Boston. Boston. Newton. Newton, Massachusetts. New Hampshire. Metropolitan Statistical Area. Greater Boston. The county government was abolished in 1997 , but the county boundaries continue to describe a state district for court jurisdictions and for other administrative purposes , such as an indicator for elections .. county. County ( United States ). Massachusetts counties also define locations for National Weather Service weather alerts -LRB- such as severe thunderstorm warnings -RRB- .. Massachusetts. Massachusetts. National Weather Service. National Weather Service. In 2010 , the center of population of Massachusetts was located in Middlesex County , in the town of Natick .. Massachusetts. Massachusetts. population. population. Natick. Natick, Massachusetts