Peach's Castle takes on the form of its Super Mario 64 variation. The exterior is made from gray brick, with four towers at each corner. At the front of the castle is a bridge leading to the double doors to enter the castle. Above them is a stained glass window of Princess Peach. In the center of the castle is a large, two-tiered tower. The castle is roofed with red shingles. Many windows also appear on various walls in the castle.
The interior of the castle has light, cream walls. The flooring consists of both checkerboard tile and red carpet, the latter being used for most stairs, pathways, and side-rooms. The doors to the individual rooms are made a dark-chocolate-colored wood.
While he does have his own house, as shown in many cases, Mario is more commonly seen at the castle. Mario even eats and sleeps at the castle, as shown on numerous occasions. The most likely reason for Mario common overnight stay is laziness, as he may just not want to go back home.
While not as commonly seen as his brother, Luigi is also a common resident of the castle. Luigi likely stays at the house when not at the castle and when Mario is adventuring, usually spending his time drinking tea, as stated in Meet the Luigi.
Toad may be the most commonly seen character in the entire castle, as he usually appears in the corner in the main room. He doesn't move very much from that specific spot, so Toad is usually caught up in the shenanigans that occur in the castle.
As he does not seem to have any other residence in the bloopers, SMG4 is the main resident of the castle. SMG4 usually spends most of his time cooped up in the right room after the stairs, as his desktop and editing equipment are commonly shown in that room. Other objects also appear in this room, most commonly a toilet.
While not staying for long periods of time, Steve commonly castle-crashes at seemingly random occasions, soon following with his signature "Hi guys!" line.
Compared to other main characters, Peach ironically appears very little in the castle. She more commonly appear during or after an incident occurs, such as when the castle burned down in Hotel Mario.
- The castle has burned down on many, many seperate occasions, but is usually repaired by the time of the next blooper.
- The exact worth of the castle is currently unknown, but the damages for the castle burning to the ground were 2 billion coins, a price not even the princess could afford.
- It's revealed in the video "Can the Villager come out to play?" that the castle was built on the top of an old mansion to which it's connected by the ventilation system. The mansion may connect with the Forgotten Door.
- Although usually portrayed as SMG4's room, the room on the right has served a number of purposes over the years. These include a bathroom, a general computer room, and Mario's sleeping quarters.