The Clarence River is a river situated in the Northern Rivers district of New South Wales, Australia. It rises on the eastern slopes of the Great Dividing Range, in the Border Ranges west of Bonalbo, near Rivertree at the junction of Koreelah Creek and Maryland River, on the watershed that marks the border between New South Wales and Queensland. It flows generally south, south east and north east, and is joined by twenty-four tributaries including Tooloom Creek and the Mann, Nymboida, Cataract, Orara, Coldstream, Timbarra, and Esk rivers. 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.

Northern Rivers is the most northeasterly region of the Australian state of New South Wales, located between 590 and 820 kilometres north of the state capital, Sydney, and encompasses the catchments and fertile valleys of the Clarence, Richmond, and Tweed rivers. It extends from Tweed Heads in the north to the southern extent of the Clarence river catchment which lies between Grafton and Coffs Harbour, and includes the main towns of Tweed Heads, Byron Bay, Ballina, Kyogle, Lismore, Casino and Grafton. At its most northern point, the region is 102 kilometres (63 mi) south-southeast of the Queensland capital, Brisbane.