Part of Ered Luin was named Ered Lindon.
The mountains stretched in an unbroken line more than 1150 miles in First and Second age. From high in the North and Ered Engrin it passed the plains of Lothlann, the land Thargelion to the furthest South of Ossiriand and then yet 250 miles further south.
In the North, as a shelter from enemies and the cold wind from Lothlann, was a spur towards the west where the pinnacle of Mount Rerir reached to the sky and here the river Greater Gelion had one of its springs. At the southern side of that mountain was Lake Helevorn and the second spring.
Near the springs of Ascar was the Dwarven-city Nogrod and 170 miles further south from that was Belegost near the springs of Adurant, the southernmost of the seven rivers of Ossiriand.
Along the northern shore of Ascar ran the Old Dwarven Road from the mountains into East Beleriand. The seven rivers in Ossiriand from Ered Luin was named, in a line from north to south, Ascar, Thalos, Legolin, Brilthor, Duilwen and Adurant. The seventh river of Ossiriand was Gelion.
Ered Luin was in First and Second age the border between East and West Middle-Earth. At the end of the First age when the world was reshaped and Beleriand and the Lands to the North was drowned beneath Belegaer a great gulf broke through Ered Luin. This Gulf is the Gulf of Lhun.
Only a small part of Ossiriand survived and is now named Lindon. In the Third age the remnants of Ered Luin is the last mountain-range before you reach the sea to the west in Eriador. At the eastern side of Ered Luin was the later kingdom of Arnor and the Elvish kingdom with the havens the Grey Havens. Opposite the river Brilthor, Duilwen and Adurant was on the eastern side of the mountains the Southern Forest who covered all of the southern lands of that side of Ered Luin.
See also Ered Lindon.