Lake Mithrim
From Tolkien Gateway
Lake of Mithrim was the body of water north of Beleriand where the Noldor first dwelt in Middle-earth: the Sons of Fëanor on the northern shore and Fingolfin's host on the southern shore.
Lake of Mithrim was the body of water north of Beleriand where the Noldor first dwelt in Middle-earth: the Sons of Fëanor on the northern shore and Fingolfin's host on the southern shore.