Well, I'm no expert, but in TH, Thorin was at the Lonely Mountain when he was speaking, and the only nearby mountains to the north were the Ered Mithrin, so he was probably referring to them.
However, Gandalf had cautioned the group to avoid the Ered Mithrin earlier on, as they were full of Orcs.
The only conclusion I can draw would be that Dwarves did inhabit certain areas of the Ered Mithrin, but not in particularly significant numbers as to retake the entire mountain range from Orcs. The ones living there most likely had very efficient defenses.
With that said, the only other areas inhabited by large numbers Dwarves at that point were the Iron Hills (which had been mentioned separately by Thorin, if I remember correctly), and the Ered Luin (too far away, and definitely not to the north).
__________________
I ♣ baby seals.
|