The county was created by the Massachusetts General Court on May 10, 1643, when it was ordered that "the whole
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According to the U.S. Census Bureau, the county has a total area of 847 square miles (2,190 km ), of which 818 square miles (2,120 km ) is land and 29 square miles (75 km ) (3.5%) is water. It is the third-largest county in M… See more

As of 2006 , Middlesex County was tenth in the United States on the list of most millionaires per county.
As of the 2010 United States Census, there were 1,503,085 people, 580,688 households… See more

The primary responsibility of the Middlesex Sheriff's Office is oversight of the Middlesex House of Correction and Jail in Billerica. It formerly ran the Middlesex Jail in Cambridge, which closed on June 28, 2014. In addition, … See more