The Towamba River is an open mature wave dominated barrier estuary or perennial river, located in the South Coast region of New South Wales, Australia.

Course and features

The Towamba River rises near Coolangubra Mountain, below Mount Marshall on the eastern slopes of the South Coast Range, part of the Great Dividing Range, approximately 9 km north of Coolangubra Mountain. The river flows generally southeast and then northeast, joined by twelve tributaries including the Mataganah Creek and Wog Wog River, before reaching its mouth, emptying into Nullica Bay, within Twofold Bay, and spilling into the Tasman Sea of the South Pacific Ocean, east of Boydtown. The river descends 533 m over its 86 km course. The catchment area of the river is 1026 km2 with a volume of 2050 ML over a surface area of 2.0 km2, at an average depth of 1.1 m. At the locality of Kiah, the Princes Highway crosses the Towamba River. The river flows through extensive parts of the South East Forest National Park in its upper reaches. In its lower reaches, the river forms the northern boundary of Mount Imlay National Park.