The Iron Hills were a range of great hills in the north-east of Wilderland. The Hills were the source of the river Carnen and rich in iron. It was also home to a Dwarf-realm of the Longbeards. The Iron Hills were rich in iron, but probably not in gold; the Dwarves of the Iron Hills, although prosperous, were not as wealthy as their other cousins.
The Iron Hills were part or a remnant of the mountain chain Ered Engrin that formed the Iron Mountains of the First Age. The Hills were mined for thousands of years by the Longbeards, being their primary source for iron above all the rest of their territories. The Dwarf-road of Mirkwood ran north-east to the Hills for the dwarf-traders and merchants between Khazad-dûm and the Hills.