Sea of Helcar

the Sea of Helkar (also spelt Helcar) was a great inland sea which existed during the First Age.

In the beginning of Arda, the Valar created the Two Lamps. Due to Melkor's deceit these were destroyed, and where Helcar, the northern Lamp had stood a great inland sea was formed, which was named the Sea of Helkar after the tower on which the northern lamp had stood.

The awakening of the Elves was at Cuiviénen, a gulf in the Sea of Helkar, and during the Great Journey they passed to the north of it through Wilderland on their way to Beleriand.

After the War of Wrath at the end of the First Age, the Sea of Helkar was drained through the Great Gulf and disappeared.

Christopher Tolkien and others have speculated that the Sea of Rhûn might "...be identified with the Sea of Helkar, vastly shrunken" (The War of the Jewels, pg. 174). In The Atlas of Middle-earth, Karen Wynn Fonstad assumed that the lands of Mordor, Khand, and Rhûn lay where the Sea of Helcar had been, and that the Sea of Rhûn and Sea of Núrnen were its remnants. In The Peoples of Middle-earth there are references to the Sea of Rhûn existing in the First Age, but no indication as to whether it should be equated with the Sea of Helkar or not.