
South River
- County:
- Middlesex County
- County Seat:
- No
- Area (mi²):
- 2.785
- State:
- New Jersey
South River borough is located in Middlesex County, New Jersey. South River borough has a 2025 population of 15,959. South River borough is currently growing at a rate of 0.09% annually but its population has decreased by -0.57% since the most recent census, which recorded a population of 16,051 in 2020.
The average household income in South River borough is $120,913 with a poverty rate of 11.3%. The median age in South River borough is 36.5 years: 35.6 years for males, and 37.6 years for females.