|Location||Northwest of Erebor, north of Mirkwood|
|Realms||Capital of Durin's folk for a time, Orc tribes, Dragon hoards.|
|Inhabitants||Durin's Folk, Dragons, and Orcs|
|Description||A rich mountain range of many ores, it has since ancient times been considered by Durin's folk as part of their territory|
|Other names||S. Ered Mithrin|
|Events||War of the Dwarves and Dragons, slaying of Scatha the Worm|
|References||Appendix A, The Hobbit, The Peoples of Middle-earth|
The Grey Mountains (or Ered Mithrin in Sindarin) was a large mountain range to the north of Rhovanion. They were the last remnants of the wall of the Iron Mountains, which once stretched all over the north of Middle-earth, but were broken at the end of the First Age.
Description, and Geography
Where the Grey Mountains met with the Misty Mountains lay Mount Gundabad, an ancient Dwarven holy site and later the capital for the Orcs of the north. During the Third Age, the branch of the Grey Mountains west of the Misty Mountains were also known as the Mountains of Angmar, as they were within the Kingdom of Angmar.
The eastern end of the Grey Mountains was split into two chains, and in between lay the Withered Heath, where Dragons bred. After that was a wide hilly plain, until the Iron Hills continued the old line of the Iron Mountains again. Erebor, the Lonely Mountain, was not part of either range.
Years of the Trees through the Second Age
Since sometime after the awakening of Durin the Deathless, the Longbeards had mined and colonized the Grey Mountains as part of their vast mountain territory. Through the First Age there was peace in the region, and the Dwarves explored and mined without hinderance. During the Second Age however after the War of Wrath, and the subsequent sinking of Beleriand, hordes of Orcs began to invade and make war against the Longbeards in the Grey and Misty Mountains as well as Mount Gundabad. However the Orcs were eventually subdued for a time, and the Dwarves went back to work.
The Third Age
After fleeing Khazad-dum Durin's folk scattered, and later gathered again in the Grey Mountains, but after six hundred years all the Dwarven strongholds had been abandoned or raided during the Wars of the Dwarves and Dragons. Its sole purpose now seemed to be to divide Forodwaith from Wilderland. Although it seems that the Orcs started moving into the mountains after the Dwarves fled, and were a large threat until after the Battle of Five Armies.
It seems that some Dwarves still dwelt in the Ered Mithrin during the late Third Age, so it is likely after the War of the Ring, the Dwarves drove whatever Drakes and Orcs were left totally from the mountains, and reclaimed the rest of their halls and mines in the Grey Mountains.