The Ered Lómin formed the western mountain-wall of Hithlum and Dor-Lómin. It was broken only by the Firth of Drengist, the passage through which Fëanor led the Noldor back into Middle Earth.

To the south of Dor-lómin, the Ered Lómin met the Ered Wethrin, and so the mountains walled off Hithlum from Beleriand to the south.

Encyclopedia entry originally written by atalante_star