Lake Hlidarvatn on the Langanes peninsula in the Northeast, has an area of 0,24 km². It is shallow and situated 9 m above sea level.

A few brooks flow through it and the lagoon Krossos and spill into the sea. Both the lake char and the brown trout in the lake are excellent. Most of the lakes in this area are also stocked with sea char and sea trout. This lake has been netted for a long time.

The distance from the capital is 643 km by the Whale Bay tunnel and 14 km from Thorshofn.