Lake Heidarvatn in Myrdalur has an area of 0,2 km². Its greatest depth is 30 m and its discharge, Kerlingadalsa, spills into the ocean a few km east of the village Vik. There is a hut with lavatories (restrooms) on the lake. The catch consists of lake char, brown trout, sea trout and the occasional salmon. Sometimes individual anglers catch up to 20 fishes per day. The worst fishing conditions are when the sun is shining brightly and sometimes the fishing is at its best in the evening. The lake is easily accessible by car.
The distance from the capital is about 190 km.