Though its design varies between games, Peach's Castle is usually a wide gray stone-brick structure with red roofs, four spire towers that support the corners, and a fifth tower extending from the main building. On the front balcony is a stained-glass portrait of Princess Peach, created by the citizens of the Mushroom Kingdom to bring them comfort when she is absent. The castle is sometimes surrounded by a moat within a hilly grassland area near Toad Town.
Peach's Castle first appeared in Super Mario 64 as the hub world, containing enchanted paintings and objects that serve as entrances leading to various courses. Mushroom Castle from Super Mario RPG may be a prototype of this location. It then appeared in various spinoffs before making a main-series return in New Super Mario Bros., in which Lakithunder attacks it to distract Mario and allow Bowser Jr. to escape with Princess Peach.
Several later games, most notably Paper Mario, Super Mario Galaxy, and New Super Mario Bros. U, have seen Bowser taking over Peach's Castle. The former two games also involve Bowser lifting the castle into space. In the Paper Mario iteration, Bowser's Castle has been built underneath to facilitate this plan; this version of his castle also made a cameo reappearance near Rainbow Road in Mario Kart: Super Circuit.
Peach's Castle has also been a stage in the Super Smash Bros. series since the very first game.