|Etymology||In honour of Charles de Fonblanque Pennefather|
|Region||Far North Queensland|
|Source confluence||Fish Creek and a series of unnamed waterways|
|⁃ location||Port Musgrave Aggregation wetlands|
|⁃ elevation||1 m (3 ft 3 in)|
|Mouth||Gulf of Carpentaria|
|south of Mapoon|
|0 m (0 ft)|
|Length||11 km (6.8 mi)|
|Basin size||3,009 km2 (1,162 sq mi)|
Formed by the confluence of a series of waterways including the Fish Creek in the Port Musgrave Aggregation estuarine wetlands, the Pennefather River flows due west, joined by the Turtle Creek from the north and Dingo Creek from the south, before emptying into the Gulf of Carpentaria south of Mapoon. The river descends 1 metre (3 ft 3 in) over its 11-kilometre (6.8 mi) course. At its widest point, the river is approximately 2 kilometres (1.2 mi) wide. The river has a catchment area of 3,009 square kilometres (1,162 sq mi), of which 349 square kilometres (135 sq mi) comprises wetlands.
In 1802 Matthew Flinders mistook the river for the Coen River named by Jan Carstensz in 1623 (now the Archer River), so that the Bosch / Pennefather River was named Coen River on maps in the 19th century. In 1880, Captain Charles Edward de Fonblanque Pennefather established that there were now two Coen Rivers, and in 1894 Queensland authorities named the river after him, although the British Admiralty Chart for the Gulf of Carpentaria kept the name Coen River until 1967.