Langisjór is a lake in the Highlands of Iceland. It is around 20 km in length and up to 2 km wide, with a total surface area of about 26 km² and a depth of 75m at its deepest point. The lake is situated rather far from civilisation at the south-western border of Vatnajökull at an altitude of 670 m above sea level. On the other hand, the environment is extremely beautiful. During the winter months Langisjór is only accessible by Super Jeeps.