Núrnen was located in the southeast of Mordor. It was fed by rivers flowing down from the outcroppings of the Ephel Dúath and Ered Lithui that separated the volcanic plateau of Gorgoroth from the fertile volcanic plains of Nurn, and its waters were described by Tolkien as "the dark, sad waters of Lake Núrnen". Its waters are often claimed to have been saltwater, but this is not supported in any of Tolkien's writings. Its waters were likely used for irrigation purposes to water the fields of Nurn.
In The Atlas of Middle-earth, Karen Wynn Fonstad assumed that the Sea of Rhûn and Sea of Núrnen were the remnants of the inland Sea of Helcar. The atlas was however published before The Peoples of Middle-earth, where it was revealed that the Sea of Rhûn existed already in the First Age, as an apparently different body of water than the Sea of Helcar.
|Seas of Arda|
- ↑ Both times Núrnen is referenced in The Return of the King (novel), it is referred to as a lake. pp. 221 and 275.