Hillsborough Township is a Township in Somerset County, New Jersey, United States. As of the 2010 United States Census, the township population was 38,303.
Hillsborough Township was originally created by Royal Charter on September 12, 1771, from portions of Western precinct. It was incorporated as one of New Jersey’s original 104 townships by an Act of the New Jersey Legislature on February 21, 1798. Portions of the township were taken to form Millstone (May 14, 1894) and Manville (April 1, 1929).
According to the United States Census Bureau, the township has a total area of 54.8 square miles (142 km2); 54.7 square miles (142 km2) of it is land and 0.1 square miles (0.26 km2) of it (0.18%) is water. In terms of area, it is the largest township in Somerset County.