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Middlesex County

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Census data reveals Middlesex County as New Jersey's most diverse

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Middlesex County Leading Together

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Welcome to Middlesex County College

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Visit Middlesex County

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Dozens Rescued, Evacuated As Henri Drenches Middlesex County, N.J.

Middlesex County is a county in the Commonwealth of Massachusetts, in the United States. As of 2016, the estimated population was 1,589,774, making it the twenty-first most populous county in the United States, and the most populous county in both Massachusetts and New England. As part of the 2010 national census, the Commonwealth's mean center of population for that year was geo-centered in Middlesex County, in the town of Natick at. Middlesex County is included in the Census Bureau’s Boston–Cambridge–Newton, MA–NH Metropolitan Statistical Area.