Nimbrethil

Nimbrethil also known as Birchwoods of Nimbrethil was a Birch-tree forest in the land of Arvernien in the south Beleriand during the First Age.

According to The Atlas of Middle-earth, Nimbrethil was about forty miles from east to west.

History
Nimbrethil's birches were used by Eärendil to build his well-known sailing-ship Vingilot. Nimbrethil was lost along with everything else in the Beleriand at the end of the First Age. The forest was recalled when Bilbo chanted the Song of Eärendil in Rivendell.

Etymology
Nimbrethil is a Sindarin word that meant 'White' or 'Silver birches'.