Mushroom Peaks is a mountainous area. The mountains extend so far it overlaps part of Sakura Village and Rubble Ruins's 2-A: Fossil Tunnel. It’s mountainous setting is also for sky mountain.
3-1: Chomproller Heights
3-2: Grimymole Mine
3-3: Butterwood Crossing
3-4: Wobbleshroom Bluffs
3-5: Fungi Pit
3-6: Bubble Basin
3-7: Slanty Shroomroad
3-Airship: Capshroom Airship" An airship with lots of capshrooms that Morton Koopa Jr is last fought in.
- The music in some of this world's levels are remixes of the theme for World 6 Map from New Super Mario Bros. Wii.
Other buildings in Mushroom Peaks:
- Mountain Mall, the shop that can be accessed after completing 3-3 (Butterwood Crossing)'s secret exit.
The bosses for Mushroom Peak.
- 3-T: In Burnblaze Tower, you fight Ricky Wrench for the first time.
- 3-C: In Moltenwire Castle, you fight Ricky Wrench for the final time.
- 3-A: In Capshroom Airship, you fight Morton Koopa Jr., one of the Koopalings.