Sømosen is a bog straddling the border between Ballerup (95%) and Herlev (5%) municipalities in the northwestern suburbs of Copenhagen, Denmark.

[2] The protected area was increased from 20 to 23 hectares in 2006.

[3] Sømosen is located between Frederikssundsvej to the south, Klausdalbrovej to the north, Lautrupparken to the west and Grønsvinget to the east About one third of the area consists of parkland.

The remaining two thirds consists of open water with several small islands and reed forest to the north.

This article about a location in the Capital Region of Denmark is a stub.