It rises in the Paparoa Range and flows through a limestone karst landscape in a roughly northwest direction for its entire length, reaching the Tasman Sea just north of Charleston.

[2] Following the discovery of gold in the area in 1866 and the subsequent founding of Charleston, increased activity around the river prompted the construction of early bridges and other infrastructure.

[7] The river starts on the eastern side of the range's main ridgeline on the slopes of The Pinnacle, flowing northeast between Mounts Faraday and Priestley through a narrow valley.

[1] Roughly a quarter of the way along its length, the river leaves the Paparoa Range, continuing to head northeast as it is joined by numerous unnamed tributaries.

[8][9] Soon after this, the land around the river narrows and develops into a short canyon, estimated to have been formed during the last million years.