The Grey Mountains were ruled by a kingdom of Dwarves, long ago, but the Dwarves were driven out by Scatha the Worm and other dragons. These mountains, according to legend, are where the Dragons who survived the War of Wrath came to dwell.
The lower slopes and foothills of this area are covered in evergreen forests. Further up, mountains of stone covered in snow. It snows here instead of raining, but snow does not accumulate beneath around y=140.
Orcs, Uruks, and Wargs of Mount Gundabad spawn here at night and can be encountered in any cave or structure.
Upon entering the Grey Mountains, the player earns the achievement "Here be Dragons?"
Glflegolas did a regional spotlight on the Grey Mountains, which may be found here. If you plan on visiting, make sure to check that out.
Ruined Dwarven Tower - Another dwarven souvenir, but these appear to be handy bases for the local Gundabad Orc Chieftains and their bands of irregular troops. GundabadBanners mark these squatted buildings and they hold chests with Orc and some dwarven loot. Forges and crafting tables of both Orcish and Dwarven origin can also be found inside. These structures can be very useful for finding dwarven forges closer to the Misty Mountains, considering that mithril can only be smelted in a dwarven forge.
Like with many major mountain ranges, gemstones are twice as common underground in the Grey Mountains as compared to most biomes, making mining here incredibly profitable. They are slightly less common in the foothills, though they are nonetheless more common there.
It is a common myth that gold is more common in the Grey Mountains than it is elsewhere. If this was ever true, it isn't anymore, possibly due to the excavations of the Dwarves.
Spruce, larch, fir and pine trees of various sizes grow in the common boreal valleys. The undergrowth is dominated by piles of needles. Only the hardiest of grasses manage to peek through the dense, acidic piles of needles covering the forested valley floors. Flowers are uncommon in this harsh, cold environment. No broadleaf trees are hardy enough to survive here. In the foothills, forests stretch for miles, with no mountains to interrupt the endless sea of trees.