The Mushroom Kingdom is one of the largest kingdoms in the Mushroom World. Under the rule of Princess Peach Toadstool, the kingdom has enjoyed and endured both a peaceful and traumatic existence. The former is largely attributed to Peach's ability to rule and the general good-nature feeling that permeates Mushroom Kingdom society. The latter is largely attributed to the Koopa Troop, a group of Koopas who reign over the badlands, and their leader, Bowser. However, because of Princess Peach's magnanimity, the Mushroom Kingdom is able to accept Bowser and his allies within its borders for various kart-racing and sports tournaments. Despite their continued belligerency, the peaceful Mushroom Kingdom never wishes for revenge against the Koopa Troop. Additionally, the Mushroom Kingdom shares its southwestern border with the Beanbean Kingdom.
The Mushroom Kingdom is a monarchy ruled by the Toadstool family. Currently, the ruler in power is Princess Peach. While King Toadstool's exact role in the government has never been confirmed, he has seemingly ceased ruling after Bowser's first direct attack on the kingdom. However, the fact that Princess Peach is not the queen may indicate that he still has political presence.
Mushroom World and Earth are almost always believed to be separate planets, though confusion does exist in the form of remarkably similar ecosystems and terrains, several species of animals and obvious human populations on Mushroom World. In other media such as the various cartoon series and comics, Earth and Mushroom World were understood to be different versions of the same planet in separate universes, and Mushroom World was noticeably cartoony and slightly surreal (eg. Pasta Land, Down Under Land). In most sources travel between the two planets is possible through warp pipes, a fact that has remained consistent throughout.