Castles are the second-largest buildings in the game. Castles can be crafted using a Crafting Table.
Castles occupy 6 chunks and 3 rooms, before update [when?], Upstairs Rooms and Underground Rooms can be picked up using Builder Tools, 2 chunks on the main floor are made of stone and 2 chunks are made of wood, when the building is placed with it's entrance facing north, the exit is slightly moved to the right, there's a glitch where the exit is in the middle, colliding with the Upstairs Room.
Square=338m
the Upstairs Room Room and Underground Rooms are not taken into account