The Irina Mountains are a location in Monster Girl Quest. A mountain range situated in the west of the Ilias continent, it was used as a base of operations for the Four Bandits. After Luka defeats the bandits, their base was left unused as the bandits became citizens within Iliasburg.
The area is very nondescript and the only notable area is the cave system used as a base for the aforementioned bandits.
In addition, as the bandits have a history of attacking travelers, it can be assumed that a trade route passes through or near the mountains, despite them being far from the central routes in the Ilias Continent.