The castle was constructed a long time before the pigs first arrived at Bird Island. The castle was passed from multiple monarchs before ending up with King Mudbeard. His coronation was held at the balcony of the palace, shortly after presenting the captured eggs belonging to the birds. He then planned a magnificent feast in order to eat the eggs together with high officials. The birds then started the Battle of Pig City which involved the destruction of the original palace as well as multiple structures in Pig City. A large hunt for Red started in the castle, with the Mighty Eagle crashing into the castle and retrieving most of the eggs as Red yelled his battle call. The castle and the surrounding structures were destroyed by a myriad of dynamite and TNT under it. The castle blew up, but King Mudbeard survived - being heavily injured, along with his assistant, Ross. The castle was then restored and rebuilt in a different style (with a face in it), then soon renovated, and making a grander, more triumphant facade, which has to be ascended by using a flight of stairs.
The palace has a vast array of rooms, including a great hall at a high portion of the castle, a bowling alley somewhere in the middle and a cavernous munitions supply cellar located underground and a kitchen place where there is a large Boiling Pot with a snout, that was meant to boil the eggs.
On the new castle, there's a large throne room, a long hallway, a kitchen, bedrooms and other rooms.
- Pigs (Other than King Pig) live in the castle.