Sommen () is a lake in the South Swedish highlands lying across the border of the provinces of Östergötland and Småland. Situated about 147 metres above mean sea level, the lake has an area of and has a maximum depth of 60 metres. Scholar Robert Norrby considered that the name Sommen originated as a noa-name – an unknown sacred or taboo name that the lake had.
History
Origin myth
Local mythology asserts that the lake was created by a cow called Urkon or Sommakoa. The lake basin was carved by Urkon with her hooves during an outburst of wrath; subsequently the basin was filled with water which became the lake. At present there are two commemorative raised stones at Fruhammar, the location of this purported event.
Age of log driving and barges
During much of the 19th and 20th century the lake was used for log driving. This activity peaked around World War I and declined as the road network around the lake improved. At present only one barge survives at the naturum Sommen museum. In 1973 log driving ceased for good.
Climate and vegetation
thumb|250px|right|Pines and birches along a cliff in lake Sommen, October 2011
Relative to other areas of southern Sweden, Sommen stands out for its low precipitation and low humidity.