The Mushroom Kingdom is a political entity ruled by Princess Peach Toadstool . During the past years of the Mushroom Kingdom, the kingdom has been invaded by the Shroobs. After they were defeated by the Mario Brothers, the Mushroom Kingdom lived numberous years of happiness. Later, however, Bowser invaded and kidnapped the Princess and her seven top servants. Mario and Luigi then journeyed to rescue her. After Bowser was defeated, this became a common thing, with the Mario Bros. always saving her. Eventually, the YTR came to stay here, living in both an old castle that once belonged to Peach and a replica known as Blooper Land, which tends to stay out of Mushroom Kingdom life.
A Hundred years later, the Kingdom still exsits, but if far futuristic, and police men have tractor beams and inescapable prisons. They also have a Time Machine in a cannon. R.O.B. seems to rule the kingdom as a dictator and the castle still appears in Peach's image.