Eiker is an agricultural area with a long history. The area was first inhabited around 8000 BC. During the early Viking Age, Eiker was the western extension of the kingdom of Vingulmark. Somewhat later, it became part of the kingdom of Vestfold.
The Old Norse form of the name was Eikjar. The name is the plural form of eiki which means "oak wood".
- Fiskum Old Church (Ringerike-Drammen District Lag. Volume 24, No.1, February 2010)