Situated at the south western end of Camden Sound and surrounded by the Montgomery Islands.
The reef is approximately 20 kilometres (12 mi) off-shore opposite Doubtful Bay (to the east) and Collier Bay (to the south). The nearest populated place is Bardi which is approximately 130 kilometres (81 mi) to the south west and encompasses a total area of 400 square kilometres (154 sq mi) making it Australia's largest inshore reef.
Covering an area of approximately 400 square kilometres (154 sq mi) and with a length of about 80 kilometres (50 mi), the reef is subject to unusual tidal movements to a maximum of 10 metres (33 ft). When the tide is out vast lagoons, sandstone islets and a central mangrove island are revealed. The outward movement of the tide forms a torrent of water, creating a river cutting through the reef and hundreds of cascading waterfalls. At low tide more than 4 metres (13 ft) of reef can be exposed.
When the tide is out-going a series of cascading waterfalls is revealed that attract migratory wading birds, feeding turtles, manta rays, black tipped reef sharks, and dugongs. The area is a popular tourist site and has several cruise operators visiting daily.