Lake Selvallavatn has an area of 0,85 km² and is located 62 m above sea level. River Fossa enters it from the east and a few small brooks from the south.
The lake does not have any discharge on the surface. It abounds in brown trout and lake char (1-6 pounders). The surroundings of the lake are very beautiful and peaceful and it is possible to drive all the way up there.
The distance from the capital is about 198 km by the Whale Bay tunnel.