Braunschweig was an influential and powerful city in the Hanseatic League, later in the Holy Roman Empire, and was an administrative seat for the Duchy (and later Principality) of Hanover.

The township got its name from New Brunswick, which in turn was named after the city of Braunschweig (called Brunswick in the Low German language), in state of Lower Saxony, in Germany.

The Straight Turnpike, now Route 1, was constructed in 1804. In the 18th and 19th centuries, the community was primarily agricultural. South Brunswick Township was incorporated by an act of the New Jersey Legislature on February 21, 1798. In 2021, SafeWise placed South Brunswick in the “100 Safest Cities in America”. placed Monmouth Junction in the top 10 of its “2021 Best Places to Live in New Jersey”. Portions of the township have been taken to form Cranbury (as of March 7, 1872) and Plainsboro (on April 1, 1919). It was formally incorporated as one of New Jersey's initial group of 104 townships on February 21, 1798. South Brunswick was first mentioned in minutes of the Board of Chosen Freeholder on February 28, 1778, as being formed from New Brunswick Township.

As of the 2020 United States census, the township's population was 47,043, its highest ever decennial census count and an increase of 3,626 (+8.4%) from the 2010 census count of 43,417, which in turn reflected an increase of 5,683 (+15.1%) from the 37,734 counted in the 2000 census.

The township is centrally located within the Raritan Valley region and is an outer-ring suburb of New York City in the New York metropolitan area. South Brunswick is a township in Middlesex County, in the U.S.

North brunswick township website