Ha Long Bay GuideHa Long Bay is in northern Vietnam, 170 km 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. HotelsFind hotels in Cat Ba Island and more. Cat BaCat Ba is an island in the Cat Ba Archipelago of Vietnam's Ha Long Bay. Cat Ba is the largest island in the Bay and approximately half of its area is covered by a National Park, which is home to the highly endangered Cat Ba langur. Quan LanQuan Lạn is an island in Ha Long Bay, Vietnam. One of the outlying islands of the Ha Long Bay region and technically in Bai Tu Long bay, Quan Lạn has been sparsely inhabited for quite some time. HalongHalong City is a town on the northern side of the Ha Long Bay Archipelago of Vietnam. Cai RongCai Rong is a city on Van Don island in Halong Bay, north Vietnam. A small port town shaped as a "T": the main road along Van Don island, and the road to the port. Cua OngCửa Ông is a town in Halong Bay, in northern Vietnam. A small town and possible stop-over on the way to Cái Rồng‎, one of the ports that provide access to the islands of Halong Bay. Ban SenBan Sen is an island in Ha Long Bay, Vietnam. Thickly forested, the island is sparsely inhabited and is probably not a viable destination for anything except quick part-day visits.