North Brunswick is a township in Middlesex County, New Jersey, United States. At the 2010 United States Census, the population was 40,742, reflecting an increase of 4,455 (+12.3%) from the 36,287 counted in the 2000 Census, which had in turn increased by 5,000 (+16.0%) from the 31,287 counted in the 1990 Census. Located south of the city of New Brunswick, North Brunswick was named for its earlier-established neighbor, South Brunswick, New Jersey. The "Brunswick" comes from New Brunswick, which was named after the German city of Braunschweig (formerly translated in English as Brunswick) or for the British royal House of Brunswick. North and South Brunswick, in turn, became the namesakes for East Brunswick. Alternatively, the city gets its name from King George II of Great Britain, the Duke of Brunswick-Lüneburg.
The area that would become North Brunswick had been settled by the Lenape Native Americans. European settlers from France and The Netherlands acquired land in 1761 from the Lenape that would become North Brunswick.
North Brunswick was first mentioned in Middlesex Freeholder Board minutes of February 28, 1779. North Brunswick Township was incorporated on February 21, 1798, by the New Jersey Legislature's Township Act of 1798 as one of the state's initial group of 104 townships. Portions of the township have since separated to create East Brunswick (February 28, 1860) and Milltown (January 29, 1889). Territorial exchanges were made with Franklin Township, Somerset County, New Jersey in 1850 and 1858, with South Brunswick in 1856 and with New Brunswick in 1860, 1917 and 1929.
According to the United States Census Bureau, the township had a total area of 12.272 square miles (31.783 km2), including 11.997 square miles (31.071 km2) of land and 0.275 square miles (0.712 km2) of water (2.24%).
Unincorporated communities, localities and place names located partially or completely within the township include Adams, Berdines Corner, Black Horse, Bodines Corner, Franklin Park, Georges Road, Livingston Park, Maple Meade, Patricks Corner and Red Lion.