Ha Long Bay (also Halong Bay ) is in northern Vientam, 170 km (105 mi) east of Hanoi. The bay is famous for its scenic ocean karst topography and is often included in lists of natural wonders of the world. It has an area of 1,500 square kilometers and has a coastline about 120 kilometers away from Hanoi. The name was based on the pronunciation in the Vietnam language Viet Nam Ha Long. Ha long Bay is a bay located in the area of the Gulf of Tangkia, north of the Socialist Republic of Vietnam.