Somerset County, New Jersey  Somerset County is a county located in the central part of the U.S. state of New Jersey. As of the 2019 Census estimate, the county's population was 328,934, a 1.7% increase from the 2010 United States Census, making it the 13th most populous of the state's 21 counties. 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 , the largest total area of any municipality. In 2015, the county had a per capita personal income of $86,468, the second highest in New Jersey and ranked 25th of 3,113 counties in the United States. Somerset County, as of the 2000 Census, was the seventh wealthiest county in the United States by median household income at $76,933 (third in New Jersey behind Hunterdon County at $79,888 and Morris County at $77,340), fourth in median family income at $90,655 (second in New Jersey behind Hunterdon County at $91,050) and ranked seventh by per capita income at $37,970 (highest in New Jersey). The Bureau of Economic Analysis ranked the county as having the 11th-highest per capita income of all 3,113 counties in the United States (and the highest in New Jersey) as of 2009. In 2012, 49.8 percent of Somerset County residents were college graduates, the highest percentage in the state. Somerset County was recently ranked number 3 of 21 NJ counties as one of the healthiest counties in New Jersey, according to an annual report by County Health Rankings and Roadmaps. Somerset County was created on May 14, 1688, from portions of Middlesex County. Somerset County is one of America's oldest counties, and is named after the English county of Somerset. The area was first settled in 1681, in the vicinity of Bound Brook, and the county was established by charter on May 22, 1688. Most of the early residents were Dutch. General George Washington and his troops marched through the county on several occasions and slept in many of the homes located throughout the area. Somerset County also played an important part during both World War I and World War II with weapons depots and the manufacturing of the army's woolen blankets. For much of its history, Somerset County was primarily an agricultural county.