Somerset County is a county located in the U.S. state of New Jersey. As of the 2010 United States Census, the county's population was 323,444, increasing by 25,954 (+8.7%) from the 297,490 counted in the 2000 Census, retaining its position as the state's 13th-most populous county. As of the 2015 Census estimate, the county's population was 333,654, representing a 3.2% increase from 2010. Somerset County is part of the New York Metropolitan Area. Its county seat is Somerville. The most populous place was Franklin Township, with 62,300 residents at the time of the 2010 Census, while Hillsborough Township, covered 55.00 square miles (142.4 km2), the largest total area of any municipality.