Quoted From Wikipedia, the free encyclopedia. Heron Island is a coral cay located near the Tropic of Capricorn in the southern Great Barrier Reef, 80 km north-east of Gladstone, Queensland, Australia, and 460 km north-north-west of the state capital Brisbane. The island is situated on the leeward (western) side of Heron Reef, a fringing platform reef of … Continue reading Heron Island