For thousands of years[citation needed] the indigenous Tharawal (or Dharwal) people called the river Deeban.

British colonial settlers named the river after Henry Hacking, a British seaman, pilot at Port Jackson and explorer in colonial New South Wales,[1] who killed the Aboriginal, Pemulwuy[4] Drawing its source from the east north-eastern runoff of the plateau above the Illawarra escarpment, drained via Kellys Creek and Gills Creek, both terminating in waterfalls adjacent to each other.

Kellys Creek rises bout 3 kilometres (1.9 mi) south of Helensburgh, east of the Princes Highway and west of Stanwell Tops.

[3] Although the Illawarra escarpment has a substantial rainfall, in dry periods, the river can be reduced to a mere trickle, resulting in connected puddles rather than a constant flow.

Its upper reaches lie adjacent to the Garawarra State Conservation Area, where it is a narrow stream in a gully within rainforest.

Significant rainforest plants growing by the river banks include white beech, citronella,[7] supplejack, Bangalow palm, jackwood and golden sassafras.

The land snail Meridolum marshalli is restricted to Royal National Park; its main habitat is wet areas near the river.

However, at its upper reaches, it has been subject to severe impacts of urbanisation (Helensburgh and Otford), timber cutting, clearing and rural activities, a large coal mine, gravel mines, leachates from Helensburgh tip and a private waste tip, sewer disposal sites, including Garrawarra Hospital, a night soil dump adjacent to Helensburgh tip and septic tank use, and the construction and use of the Princes Highway and Sydney to Wollongong railway.

Furthermore, runoff from the towns of Helensburgh, Otford and Stanwell Tops (which lie above the catchment) has also impacted on water quality in the river, resulting in increased turbidity and algal growth.

In the mid-19th century shell grit was in high demand as a source of lime for building in the Sydney district.

Within the Royal National Park at Audley, visitors have enjoyed picnic and boating facilities for more than a hundred years.