Mountain
From MHWiki
The Mountain is a location in Gnawnia accessible only to hunters of the rank Journeyman and higher. In the original rollout of Mousehunt in March of 2008, the Mountain was the 'last' location, the areas of Burroughs and Furoma not yet having been created.
Ninja mice from the Mountain may drop a map piece to the Laboratory, which Master hunters can access. Other mice types that live here are White mice, Brown mice, Gold mice, Diamond mice, Granite mice, Dwarf mice, Steel mice and the occasional Mole mouse. Mice can steal points, gold, and cheese from a hunter while in the Mountains.
This treacherous environment only allows the toughest of mice to survive. Be warned: the Mountain is no place for the novice mouse hunter!