The Acorn Archipelago is a location that appears in the Sonic the Hedgehog comic series and its spin-offs published by Archie Comics. It is a series of islands that make up the Kingdom of Acorn, the capital of which, Mobotropolis, is located on Westside Island.
In ancient times, the Acorn Archipelago was a single island called Pancardina. The Trolls of the Second Great Civilization would live here in harmony, harvesting crystals from the Hidden Palace Zone to increase their power. However, they were wiped out overnight by an unknown powerful being, with Pancardina scattering into a series of islands.
One of these islands was called Westside Island and there the Kingdom of Acorn was established in the Royal Hills Zone, the current reining monarch being King Nigel Acorn. Shortly following the retirement of Dr. Ellidy, King Acorn collaborated with two former G.U.N. scientists, Dr. Eggman and his apprentice Dr. Julian Snively. Secretly organizing a takeover, they convinced the king that the United Federation was planning to seize the kingdom for personal gain. The king secured them positions in the royal court for their efforts, allowing the villains complete access to the islands' resources. Eggman's forces began working to strip-mine South Island while constructing the Death Egg on Westside Island, and to hunt down the Chaos Emeralds. The King eventually caught on to their evil scheme but he was banished by the doctor to the Special Zone before he could act alongside Naugus.
As Eggman's invasion commenced, Princess Sally and the other children within Mobotropolis were spirited away by Rosie Woodchuck and Professor Charles to Knothole Village in the Wood Zone. Rotor had the misfortune of arriving in the city during the coup and was forced to quickly retreat to Knothole with everyone else.
- Sonic the Hedgehog #281, "The World of Sonic the Hedgehog"
- Sonic Universe #89, "Shattered Part 3: Lost & Found"
- Sonic Universe #88, "Shattered Part Two: Lies & Half-Truths"
- Sonic Super Digest #12, "Sonic Comic Origins: The Traitor"
- Sonic/Mega Man X Free Comic Book Day 2014, "Sonic Comic Origins: Sally--The Exiled Leader"
- Sonic the Hedgehog/Mega Man X Free Comic Book Day 2014, "Rotor–The Exiled Inventor"