It descends 256 metres (840 ft) over the course of its 394-kilometre (245 mi) length and empties into the Coral Sea in the South Pacific Ocean, between Iluka and Yamba.

[citation needed] The extremely intense rainfalls that typify the North Coast mean, however, that major floods can temporarily raise the flow of the Clarence to 24 feet, as happened in 1890.

[5] The climate of most of the basin is subtropical (Köppen Cfa), though the highest areas with cooler weather are of the temperate Cfb type.

During Cyclone Oswald, the Clarence was subject to minor flooding, brought about due to the storm's residual effects and associated monsoon trough that passed over parts of Queensland and New South Wales.

[citation needed] Most of the Clarence basin is heavily forested, with important areas of remnant subtropical and temperate rainforest occurring all along the course.

Of particular interest is the small island town of Harwood, where a Sperry New Holland factory and a quaint Bush Pub overlook the Clarence delta.

[1] The river remained unknown to British authorities until the mid-1830s when escaped convict Richard Craig, who had been living with Aboriginal people in the area, reported its existence.