Town Hall Address 48 Washington St. South River, NJ 08882-1247 United States- Middlesex County Website http://www.southrivernj.org County Clerk 732-257-1999 Ext. 116 48 Washington St. South River, NJ 08882-1247 United States County Admin 732-257-1999 Ext. 120 South River, NJ 08882-1247 United States Assessor 732-257-1999 Ext. 123 Monday & Wednesday: 6:00 P.M. - 9:00 P.M., Saturday: 9:00 A.M. - 12:00 P.M. 48 Washington St. South River, NJ 08882-1247 United States Tax Collector 732-257-1999 Ext. 103 48 Washington St. South River, NJ 08882-1247 United States Attorney 732-636-3344 48 Washington St. South River, NJ 08882-1247 United States Mayor 732-257-1999 48 Washington St. South River, NJ 08882-1247 United States Municipal Court 732-257-1233 61 Main St. South River, NJ 08882-1293 United States County Middlesex