- For the version of this location after the Super Genesis Wave, see Castle Acorn.
Castle Acorn is a location that appears in the Sonic the Hedgehog comic series and its spin-offs published by Archie Comics. It is the seat of Mobius' ruling monarchy, the House of Acorn, and is the crown jewel and primary hub of the Kingdom of Acorn's capital.
Previous versions of Castle Acorn existed in Robotropolis (which became the command center of Dr. Ivo Robotnik after his military coup and was destroyed by O.T.I.S.), and later Knothole (which was destroyed by Dr. Eggman's attack on Knothole).
Another incarnation of the castle was built by Nicole via nanites in memory of the splendor of Old Mobotropolis, and serves as the home of the Royal family. Since Royal Army General Amadeus Prower's revolution (which served to re-form the Kingdom into the Republic of Acorn) it also became the primary meeting place for the Council of Acorn, with the counselors all having offices and optional residences inside the Castle.
The castle was later destroyed by the Battle Bird Armada during their attempt to excavate Babylon Garden. NICOLE eventually restored it, only for it to start breaking up due to the efforts of Tails Doll.
- Sonic the Hedgehog #43, "The Dream Zone"
- Sonic the Hedgehog #70, "Saving Nate Morgan"
- Sonic the Hedgehog #110, "Station Square Attacks!"
- Sonic the Hedgehog #175, "Eggman Empire"
- Sonic the Hedgehog #176, "Cracking the Empire"
- Sonic the Hedgehog #178, "House of Cards Part 1 of 2"
- Sonic the Hedgehog #179, "House of Cards Part Two: Royal Flush"
- Sonic the Hedgehog #209, "Iron Dominion Part 2"
- Sonic the Hedgehog #210, "Home Invasion Part One: Breaking and Entering"
- Sonic Universe #36, "Babylon Rising Part 4: Resurrection".
- Sonic the Hedgehog #247, "At All Costs Part One: Fate Interrupted"