Hillsborough Township is a township in Somerset County, in the U.S. state of New Jersey. Located in the Raritan Valley region, the township is a suburban and exurban bedroom community of New York City within the New York Metropolitan Area. As of the 2020 United States census, the township's population was 43,276, an increase of 4,973 (+13.0%) from the 2010 census count of 38,303, which in turn reflected an increase of 1,669 (+4.6%) from the 36,634 counted in the 2000 census.