The Carnarvon Basin is a geological basin located in the north west of Western Australia. This is the main geological feature that makes up the North West Shelf. The onshore part of the Carnarvon Basin covers about 115,000 km² and the offshore part covers approximately 535,000 km² with water depths up to 3,500 metres. It is separated into two major areas - the Northern Carnarvon Basin, and the Southern Carnarvon Basin.