Lake Elliðavatn is in Heiðmörk, which is an outdoor recreation area on the outskirts of Reykjavík and Kópavogur. The lake belongs to both Reykjavík and Kópavogur. Access to the lake is by the Heiðarmerkur road and through Kópavogur to get to the Vatnsendaland of the lake.
Elliðavatn is the most popular fishing lake in the capital area and is very productive. The lake is at 73 m above sea level and is about 1.8 km² in area. The maximum depth is just over 2m, with the average depth about 1 m. The creeks, Bugða and Suðurá flow into the lake. The fish species in the lake include Arctic char, brown trout, salmon, and occasional sea trout. Arctic char was predominant in the lake but in the last decade brown trout populations have been increasing so that they are becoming the most common fish species in the lake. Salmon and sea trout migrate into the lake from Elliðaá into the tributaries. The size of the brown trout caught in the lake has been increasing with fish up to six pounds caught.