From 1683 to 1720, the area was commonly referred to as South River Landing. In 1720, the name Willettstown was adopted after settler Samuel Willett. In 1784, the name was changed to Washington and the area was variously referred to as Washington Village, Washington Woods, and Little Washington. The name was considered at the suggestion of Abraham Barkelew, one of the original settlers in the town. In 1870, the name was changed to South River and on February 28, 1898, South River officially became a borough.
South River is a borough in Middlesex County, in the U.S. state of New Jersey. As of the 2020 United States census, the borough's population was 16,118, an increase of 110 from the 2010 census count of 16,008, which in turn reflected an increase of 686 from the 15,322 counted in the 2000 census