The Iron Hills were a range of hills in the northeast of the known parts of Middle-earth, in the middle part of both Rhovanion and Rhûn, east of the Lonely Mountain. The Iron Hills were the last remains of the Iron Mountains where Morgoth dwelt.

The Grey Mountains 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. North of the Grey Mountains lay the Northern Waste.

Aglarond ("Place of Glory") was a name for the Hornburg as well as the Glittering Caves behind it at Helm's Deep. After the war, Gimli the Dwarf, who had fought mightily in that battle, established a colony of Durin's folk there. Gimli became known as 'the Lord of the Glittering Caves'. The Dwarves of Aglarond restored the Hornburg following the War of the Ring, and it became a shared fortress between them and the Rohirrim.