Long Island, small land mass in the Cumberland Islands, 0.5 mile (1 km) off the northeastern coast of Queensland, Australia, in Whitsunday Passage of the Coral Sea. One of the inshore, coral-fringed, hilly continental islands of the Great Barrier Reef, it measures 6 miles by 1 mile (10 km by 1.6 km) and rises to 370 feet (113 metres). Long Island is a national park and holiday resort. Its principal settlements, at Happy and Palm bays, are reached from the mainland by launches from Shute Harbour (west).