Region (pronounced Reh-gi-on) was the main forest of Doriath, which made up the majority of this elven realm.
It lay between the rivers Aros and Esgalduin, both of which were completely surrounded by the Girdle of Melian. The capital city of Menegroth stood near its northern bounds.
The forest consisted mainly of holly trees.
Eöl, the Dark Elf, once dwelt there in the early days, but was not content and obtained permission from the king to dwell outside its boundaries, in exchange for the sword Anglachel.