Langøya is the third largest island of Norway (except for Svalbard), with an area of 850.2 square kilometres (328.3 sq mi). The island is a part of Vesterålen, and is situated in Nordland county, just west of Hinnøya. The Sortlandssundet (sound) divides the two islands. It includes the municipality of Bø, and parts of the municipalities of Øksnes, Sortland and Hadsel. There are several lakes on the island, like Alsvågvatnet.