Elves of Sirion
From Tolkien Gateway
A short-lived Elven culture that grew up in the lands around the Mouths of Sirion during the last days of the First Age. Its people were Elves that had fled from the destruction of the great realms of Beleriand, especially Gondolin and Doriath. It was itself destroyed, not by Morgoth, but by the remaining Sons of Fëanor who sought the Silmaril of Elwing, who dwelt with the Elves of Sirion.