The Mushroom Kingdom is a kingdom that is part of Mushroom World. It is located on the Mushroom Continent, where it occupies a significant portion of its landmass. Its capital city is Toad Town, which is also the capital city of Mushroom World. Princess Peach Toadstool is the reigning monarch and head of state. Toads make up the majority of the population of the kingdom, with smaller groups of Humans, Goombas and Koopas also present.
It is surrounded by the Beanbean Kingdom to the southwest, the Oho Ocean to the southeast, the Koopa Kingdom to the east, along with many smaller domains and undeveloped wilderness. It is the principle, governing kingdom of Mushroom World.
The Mushroom Kingdom's terrain is extremely varied. Its most prominent biome is a characteristic grassland punctuated by domed hills, but high alpine terrain, forests, and deserts such as Dry Dry Desert also exist within the kingdom. The kingdom has settlements of all sizes, ranging from small towns such as Koopa Village all the way to large metropolis such as Mushroom City and Toad Harbor.
The Mushroom Kingdom has well developed terraforming, construction, and scientific infrastructure, being capable of creating megastructures such as the Mario Kart Stadium and the Baseball Kingdom.The Kingdom's power comes from its Power Stars, a uniquely star-shaped variation of the Power Moons. Stars form a major part of the kingdom's iconography and culture: most Toads follow a belief system involving the Star Spirits, who are believed to grant wishes. Sports events such as anti-gravity kart racing, golf, and tennis have become highly popular during Princess Peach's reign, drawing large crowds to see her compete with other royalty, local heroes, and companions. Mushrooms, which are the namesake of the kingdom, are also deeply ingrained in the culture: Toads are closely related to fungus. While Toads are the predominant species in the kingdom, historically, the Mushroom Kingdom has relied on Humans for leadership.
Since the reign of Princess Peach, the Mushroom Kingdom has been defending in a protracted war with the Koopa Kingdom. The military of the Koopa Kingdom, the Koopa Troop, currently occupies much of the kingdom, including many castles. Princess Peach has been abducted numerous times by the king of the Koopa Kingdom, Bowser Koopa.
- Kingdoms form parts of Mushroom World, which is a single empire composed of several smaller Kingdoms. In general, a "Kingdom" may not be independent or organized.