Mushroom World

Mushroom World often refers to the eight countries from Super Mario Bros. 3. The Mushroom Kingdom serves as a gateway to these lands. In Super Mario Bros. 3, King Bowser's Koopalings have taken over the other seven kingdoms of the Mushroom World. They stole the Magic Wands of the kings of each domain and transformed them into various creatures. While Mario and Luigi eventually defeat them and restore the kings to normal, Bowser himself returns to the Mushroom Kingdom and kidnaps Princess Peach once again, but is thwarted in his own territory.

While the Mushroom World originally seemed to exclude the Mushroom Kingdom, later uses of the term apparently count Princess Peach's sovereignty as well. In Yoshi's Safari, it is stated during the ending that Mario and Yoshi departed from Jewelry Land to return to the Mushroom World, where the princess awaits them. In addition, Mushroom World is sometimes used to refer to the Mushroom Kingdom in Paper Mario. This is due to the fact that the original Japanese script of the game explicitly refers to the nation as the Mushroom World, and the English localization substituted most of that usage with the more common Mushroom Kingdom in the context of the story. A similar practice existed in the manual of Super Mario World, where the reference to the Mushroom World from the previous title was also changed to the Mushroom Kingdom in translation.

Lands
The Warp Zone is considered World 9, but it is not confirmed to be an official part of the Mushroom World. Likewise, it is unknown where the Advance-exclusive World-e is located.

Trivia

 * On the back of The Super Mario Bros. Super Show! Volume 1 DVD, it is mentioned that Mario and Luigi transported into the Mushroom World. However, as shown on other home video release boxes, this was mistaken for the Mushroom Kingdom, which is usually referred to as "Mushroom Land" in the cartoon series.