The river Elliðaá is situated in the Reykjavík area in the south-west of Iceland. Two small rivers have their source in the volcanic mountain range of Bláfjöll and stream down to the lake Elliðavatn in the eastern suburban border of the city, its outlet forming the river. On their way, they pass through the nature reserve area of Heiðmörk.
On its way to the sea, which is reached in the bay Elliðavogur in Reykjavík, not far from the open-air folk museum of Árbæjarsafn in Árbær, the river cascades over several small waterfalls within the boundary of the city.
Salmon fishing in the river is excellent although very expensive.
The valley Elliðaárdalur is one of the green recreational areas of Reykjavík with hiking and bicycle paths. There are also a swimming pool, a small ski lift and horse riding facilities in the valley.
Since the beginning of the 20th century, this has also been a reforestation area with birches, firs and pine trees.
Very interesting and varied bird life is to be found in the valley including swans and 8 different species of ducks. All together, 60 species of birds can be found here. There are also many song birds such as the thrush.
In 1921, the first hydroelectric power station in the country was constructed here and is still in use. A museum in the building tells the story of the electrification in Reykjavík.
The base of the valley is a lava field dating from a volcanic eruption 4500 years ago in the Bláfjöll mountains some 25 km away from the city.