The home of the Folk of Durin, the Longbeards (see Dwarf (Middle-earth)), after they were driven from their ancestral home of Khazad-dûm.

The Grey Mountains were the last remnants of the wall of the Ered Engrin or Iron Mountains, which once stretched all over the north of Middle-earth, but were broken at the end of the First Age. North of the Grey Mountains lay Forodwaith, or the Northern Waste. This land was known as Dor Daidelos during the First Age, but most of it was destroyed in the breaking of Arda.

The Iron Hills is one of the seven kingdoms of the race of Dwarves and was founded by Grór son of Dáin I after the Dwarves were exiled from the Grey Mountains to the west (And south, see Thrór and Erebor) because of attacks by Cold-Drakes seeking the vast wealth of the mountains, which resulted in the death of the king Dáin I. The Iron Hills were colonized at around the time of 2500 of the Third Age.

Galadriel's Ring enriches the land by preserving its flora from death and decay, and in wielding it she has created a powerful ward against all creatures of evil intent: in fact the only way that Galadriel's Lothlórien could have be conquered by Mordor is if Sauron himself, the master of all the Rings of Power, comes there.

The forest holds the dwelling of a Silvan Elven realm ruled by Sindarin lords, firstly the Elvenking Oropher and subsequently his son Thranduil after the fall of Sauron. It had been called Greenwood the Great or Eryn Galen until around the year 1100 of the Third Age, when a "shadow" fell upon it, and men began to call it Taur-nu-Fuin and Taur-en-Daedelos in Sindarin.

The most important passes are the High Pass and the Redhorn Pass. There is also a pass at the source of the Gladden. The Gap of Rohan is the valley (probably of the River Isen) between the southernmost peaks of the Misty Mountains and the northernmost of the White Mountains. There may also be a gap between Mount Gundabad in the Misty Mountains and the westernmost extremity of the Grey Mountains,