It is situated in the Scandinavian mountain range, at a height of . The town of Arjeplog is located on its south-western shore. The lake then extends northwest up to the town of Jäckvik, containing about 400 islets, many of which have distinguishable flora and fauna. Research on the ecosystems comparing the larger islands with smaller islets in Hornavan and Uddjaur are popular due to their unpolluted environment, and have yielded . In June 2005 an international study was published in Nature entitled Effects of species and functional group loss on island ecosystem properties.
