The Castle began as a small village where its inhabitants built a wall and a ditch around it to keep out wolverines, witches and warlocks. As time went on, the walls were expanded, and more houses were built. Later, when a baby was stolen by the Darke Forest Creatures, they worked on the wall they have now and they dug the ditch deeper. On MidSummer Day, they breached the banks between the ditch and the Moat was built.
The summer before the Moat was built, a pretty barge arrived with a young woman and three daughters. They had dark hair, violet eyes and spoke a different language. The woman was given the best house and was made Queen. Her house later becameThe Palace. She never explained where she came from or why she left.
Many years later, when one of the queens descendants was Queen, Hotep-Ra arrived and healed the Queen's daughter, who was ill. For this, he was made the first ExtraOrdinary Wizard and built the Wizard Tower.
- The Palace: The place where the queen and her family live. Currently, Jenna Heap, Sarah Heap and Silas Heap live there. The Custodians resided there for ten years after the assassination of the queen.
- The Manuscriptorium: Scribes work copying spells and documents there. The Chief Hermetic Scribe leads a team of scribes in their work in copying out documents. The Conservation Scribe lives in the basement.
- The Ramblings: A series of apartment-like places in which poorer residents of the castle live. When the citizens started running out of room to live, The Ramblings were built. This is where the Heaps and lived before Jenna learned she was the Princess.
- The Wizard Tower: The 21-story tower where the ExtraOrdinary Wizard, his/her apprentice, and the Ordinary Wizards live. There are a set of silver stairs that move according to how quickly you'd like to go up or down them.
- The Ice Tunnels: A series of tunnels underneath The Castle which are completely covered in ice. However, 500 years ago, there was no ice. Marcellus Pye and Esmeralda froze the tunnels for an unknown reason. These tunnels run from the castle, under the ocean, through the Peepe on the Isle of Syren, all the way to the House of Foryx. Septimus and Beetle have much fun in these tunnels playing with the Wizard Tower sled.
- The Great Chambers of Alchemie and Physik: this is the place where Septimus Heap was taken to after being dragged through the looking glass out of his own time by Marcellus Pye and Queen Etheldredda in Physik. He lived there as the Alchemie apprentice for a long time until he was reacued.