Mt. Steel (ハガネやま, Mt. Hagane) is the third dungeon traversed in Pokémon Mystery Dungeon: Red Rescue Team & Blue Rescue Team. It is also the first dungeon to feature a boss Pokémon: Skarmory. Your mission in the dungeon is to make your way to the ninth floor, then fight Skarmory to save Diglett. Once you have completed this mission, Skarmory will no longer be found in Mt. Steel. To be able to go on this adventure, you must have already saved Magnemite from Thunderwave Cave, and completed two missions since.
This dungeon is mainly inhabited by Steel-Type Pokémon and consists of nine floors. There are no monster houses, shops, or traps in this dungeon.