Lake Hvalvatn has an area of 4,1 kmē, it reaches a depth of 180 m and lies 378 m above mean sea level. It is the second deepest lake of the country. Its discharge is Botnsa, which spills into the Bay of Whales (Hvalfiord). The approach to the lake is over route 52 from the so-called Vidiker area. The lake's surroundings are beautiful.

Only lake char has been caught in the lake. Just east of the lake are smaller lakes called Krokatjarnir with lake char as well. In the northern slopes of Mt. Hvalfell there is a cave, which was once occupied by an outlaw for short period of time.
The distance from the capital is about 75 km.