The Great Barrier Reef is the world 's largest coral reef . It is located close to the coast of Queensland , Australia . The Great Barrier Reef is the world 's largest reef system composed of over 2,900 individual reefs and 900 islands stretching for over 2,600 kilometres ( 1,600 mi ) over an area of approximately 344400 k. The reef is located in the Coral Sea , off the coast of Queensland in north-east Australia .