Eidselva lies in Nome municipality in Telemark. It rises in Flåvatn, and runs into Norsjø in Ulefoss. The river is part of Skiensvassdraget, and an important part of the Telemark Canal. On the stretch from Ulefoss to Flåvatn there are six sluices (14 sluicegates), with a total rise of around 57 metres (187 ft). In the river, there are four hydroelecric power stations: Eidsfoss, Vrangfoss, Ulefoss and Aall-Ulefoss.