Places in Middle-earth
Location: It is described in Morgoth's Ring as "Northward in Valinor, in the hills near to the halls of Mandos..."
Description: "...they made a strong place and treasury in the hills; and there at Formenos a multitude of gems were laid in hoard, and weapons also, and the Silmarils were shut in a chamber of iron."
The Silmarillion, Ch 7, Of the Silmarils and the Unrest of the Noldor
Contributors: Lyllyn 9.10.03