Castle Dedede

King Dedede's Castle, sometimes referred to as Castle Dedede or just Dedede's Castle, is a recurring location in the Kirby series. In all games, this castle serves as King Dedede's home and sometimes the last level. It is apparent that Dedede has multiple castles.

Castles in the games

Kirby's Dream Land/Spring Breeze/Revenge of the King: located on the peak of Mt. Dedede. The windows appear to look like scowling eyes, which turn to sad-looking eyes after Dedede is defeated.
Kirby's Dream Land 2: Dark Castle, a large palace taking up the bulk of the last Rainbow Island. The castle is similar in appearance to the one on Mt. Dedede.
Kirby's Dream Land 3: located at the edge of Iceberg. It is a strange tower that shares King Dedede's color scheme, but contains the looming eye of 0.
Kirby 64: The Crystal Shards: located in or near a forest. Compared to other castles, this fort is relatively small and cozy, lasting only one level.
Kirby: Squeak Squad: located on a cliff in Prism Plains. This castle resembles its counterpart in Kirby: Right Back at Ya!. In fact, there is a device in King Dedede's room that resembles the teleporter in the anime, where King Dedede receives monsters from Nightmare Enterprises. After the initial confrontation with Dedede, if Kirby returns to Prism Plains, it can be seen that the castle's main chamber and roof had collapsed. Either the Squeaks broke it during their break-in or Dedede threw Kirby into them with such force that it caved in the roof.
Kirby's Epic Yarn: located on a hill somewhere in Dream Land. When Yin-Yarn took over, it became a floating stronghold. It looks like the castle from Kirby: Right Back at Ya!, and is known as "Castle Dedede."
Kirby Mass Attack: located on an island in the middle of Dedede Resort. It's made up of four walls, four towers, and a giant dome in the middle. The interior is made of sweets.
Kirby: Triple Deluxe: located at the top of the Dreamstalk next to Kirby's house. Appears to be the very same castle seen in Kirby's Dream Land and Kirby Super Star.
Kirby: Planet Robobot: the same castle seen in Kirby: Triple Deluxe. It is destroyed by the Access Ark in the game's opening.

In Kirby: Right Back at Ya!

King Dedede has many castles throughout the Kirby games, though he only seems to have one in Kirby: Right Back at Ya!.

The castle is made of yellow bricks on the outside, with the towers having red tops. It has a fountain and courtyard in its outside. The inside of the castle has green bricks in its walls throughout the hallways. The castle consists of Dedede's throne room, which has a monster transmitter that is linked to the one in the command center of Nightmare's Fortress, as well as Tiff and Tuff's family's living room, Meta Knight's living room, the dining hall, the castle kitchen, the bathrooms, Dedede's bedroom and balcony, Escargoon's bedroom, the library, and even the dungeon, where the Channel DDD studio is located. Various statues of Dedede himself, as well as his faceprints, can be seen throughout the castle. One of the castle's towers also has an observatory in it.

Trivia

Dedede Arena
Dedede's Castle appears in the distance in Kirby and the Rainbow Curse's introduction.
King Dedede's Castle in Kirby 3D Rumble

In Kirby: Triple Deluxe's Kirby Fighters sub-game, there is a stage based off of the arena in which Kirby duels King Dedede. Dedede Arena, as the stage is called, is based more off the Kirby Super Star incarnation than any other. This stage reappears in Kirby Fighters Deluxe.
King Dedede's Castle can be seen in the background of the intro of Kirby and the Rainbow Curse, where it appears as it does in Kirby: Triple Deluxe.
By using the C-Stick on the New Nintendo 3DS, the player can find King Dedede's Castle in the distance in the Kirby 3D Rumble sub-game.