The Brunswick River is a wave-dominated barrier estuary with an open entrance on the north coast of New South Wales. Training walls extend out to sea to ensure the entrance to the estuary remains open.
- Marshalls Creek (North Arm)
- Brunswick River (Main Arm)
- Simpsons Creek (South Arm).
Other tributaries of Brunswick River include Mullumbimby Creek and Kings Creek.
Brunswick River estuary supports extensive wetland areas, including the nationally significant Billinudgel Nature Reserve, which is listed in the Directory of Important Wetlands in Australia.
The estuary is a central feature of the town of Brunswick Heads, which is a popular destination for recreational beach activities and river fishing. The estuary supports a range of commercially important fish and provides significant shorebird habitat. Over 20 square kilometres of wetlands within the Brunswick River catchment are protected under State Environmental Planning Policy (Resilience and Hazards) 2021.