Eikeren

Eikeren or Eikern is a long, deep lake in eastern Norway. The lake is located on the border of Øvre Eiker Municipality in Buskerud county and Holmestrand Municipality in Vestfold county (the majority of the lake is in Buskerud). It is the largest lake in all of Vestfold county, measuring about long and wide, and reaching a depth of .

The village of Eidsfoss lies at the southeastern end of the lake. At Eidsfoss, water flows into the lake from the nearby lakes Bergsvann, Vikevann, Haugestadvann and Hillestadvann. Eikeren lake also receives water flowing into it from the rivers Hakavikelva and Steinbruelva. The lake flows out through a narrow strait (Sundet) on the north end of the lake. The strait flows into a smaller lake Fiskumvannet. Through this strait, water flows at an average rate of . From Fiskumvannet, water runs out into the river Vestfosselva to the village of Vestfossen. The river then goes on to the town of Hokksund, where it splits into two rivers that both flow in the large river Drammenselva.