Lake Helevorn was a dark and deep lake near the foot of Mount Rerir in the northern Ered Luin. It was one of the sources of the River Gelion which would its long way south through Beleriand.

Caranthir and his people lived on the lake’s shoreline, but the lake itself was defiled by Glaurung the dragon and the Morgoth’s orcs in Dagor Bragollach.