The “Meres of Twilight”. The name given by the Elves of Doriath to the region of marshes that bordered their forested land in the southwest, where the Aros flowed into the Sirion. Here the Sirion split up into smaller streams, running through a wide floodplain of fens, before gathering together once more into the Falls of Sirion.

The Meres were part of the Girdle of Melian - the protective circle of enchantment woven around Doriath by Melian.