Mushroom Hill Zone

thumb|250px|right|Act 1 Themethumb|250px|right|Act 2 Theme

The Mushroom Hill Zone (referred to as the Mushroom Valley in Sonic 3 ' s level select mode) is the first zone in Sonic & Knuckles (7th Zone in Sonic 3 & Knuckles). It is a lush forest notable, as its name would suggest, for giant mushrooms that can be used as various springs and platforms. The mini-boss of this stage, Hey Ho, wields an axe and chops sections of tree trunks to throw at the player. It is a large forest filled with hills and giant mushrooms.

In the first act, when playing as Sonic, Tails will airlift Sonic down from the freefall after stopping the Death Egg's launch. Sonic then spies Knuckles closing the door to a passageway leading to a Warp Ring for Special Stage. In the complete game, Knuckles is hiding a Super Warp Ring that takes the user to the island's Hidden Palace Zone. Here all collected Chaos Emeralds' powers are halted by the Master Emerald and they are transformed into dormant Super Emeralds. From this point on, Super Warp Rings (distinguishable by the colors of the Emeralds which it flashes) transport you to the Hidden Palace Zone for another chance at a Super Emerald. Mushroom Hill Zone contains lots of Warp Rings compared to other zones in Sonic & Knuckles, making it important to collect as many Emeralds as possible before leaving this zone if aiming to collect all seven before completing the game (there are at least six in this level alone).

When playing as Knuckles, we find him relaxing and enjoying his playful friends when Egg-Robo, sent by Eggman, appears and tries to destroy Knuckles with a well placed bomb. Knuckles gives chase, and the game proceeds often with secondary paths not available to Sonic & Tails.

The second act takes place on a desperate run through the forest to stop Eggman from destroying it by means of a weather machine that rapidly progresses the seasons from spring, through summer and autumn and into winter. Through different sections, the color of the forest will change from green to red to tan. At the end, you must destroy the weather machine (in the form of a satellite dish in the ground) to turn the forest back to green and trigger the boss fight. It's basically a high-speed limbo game. Avoid the spike bars and attack Eggman. Once you have defeated him, you will witness a scene with Eggman escaping onto the next area, Flying Battery Zone.

Other appearances
The Zone returns in Sonic the Fighters the area set up on a giant tree stump surrounded by giant mushrooms. In story mode this is the stage Espio is fought on.

In the Archie Comics continuity, Espio claims this is his native zone. This later turns out to not be the case.

In Sonic the Comic, the entire population of the Emerald Hill Zone was temporarily re-located to the Mushroom Hill Zone (also occasionally referred to as the Mushroom Valley) in order to protect them from Doctor Robotnik.

Appears in

 * Sonic & Knuckles
 * Sonic 3 & Knuckles
 * Sonic Heroes (mentioned only)
 * Sonic Championship