A race of Orcs that inhabited the Misty Mountains. They were of a recognisably different kind to other Orcs, being somewhat larger than most, and well adapted for life in their tunnels beneath the Mountains. Their most important contribution to history was at the beginning of the Third Age, when they descended from their Mountains to attack Isildur as he rode home from the War of the Last Alliance. Thus, the Orcs of the Mountains were directly responsible for the loss of the Ruling Ring that Isildur carried.

Long centuries after that fateful raid, their chieftain Azog slew the Dwarf-king Thrór, and so triggered the long War of the Dwarves and Orcs. After that War, most of the Orcs of the Mountains were slain or scattered, but some survived under the leadership of Azog's son Bolg. They still had a part to play in history: not least because it was the capture of Bilbo Baggins and his companions by a band of these Orcs that led to the finding of the Ring - the same Ring their ancestors had caused to be lost nearly 3,000 years before.