The Shimon Island is a large Island that exists off the coast of Japan. The island was the home of Cozart Shimon after he left Italy and is the current family's base of operations.
The Island is located just off the coast of Japan. It has many different areas on it that are significant to different events important to Shimon. A path carved into the stone will lead people around the island. The island itself also has special defensive capabilities that are controlled by mist or desert flames. The island is capable of being concealed from normal view and that of radar and is capable of blocking outside mental energies like those of illusionists.
House
Th island has a large house built into the rock along part of the islands coastline. Enma's family resides here while fighting the Vongola. With the revelations of the third key we see this is also where Cozart lived while on the island.
Forest
This was the location of Koyo Aoba and Ryohei Sasagawa's boxing match. It was filled with plants that had grown since the time of Primo and had apparently tasted the blood of Cozart and Giotto's battle. However most of them were blown away by Ryohei's final attack, leaving a barren field.
Cave
This was the location of Rauji Ooyama and Lambo's sumo match, found on accident while Lambo chased after a bunny, leading to Gokudera, Tsuna, and Lambo to fall down into the hidden cave. A large underground cave with a raised platform that acted as the ring. Rauji claimed that the structure was unstable and certain rocks were essential to its structure. The cave was similar to structure to where Shimon was betrayed.
Town
It was the site of P.Shitt and Gokudera's battle. A small town that was built on the island and a replica of the town where Cozarts Shimon and Giotto first met, founding their respective families. Enma and Tsuna later fought there and demolished several sections.
Waterfall
The waterfall was the site of the battle between Adelheid and Hibari.
Castle
A large underground castle built in the European style. It is located in a large cave with a winding stone path that leads to it. It has many large spires and a throne room.
Circular Building
This temple like building exists on the top of a large hill on the island with a long stone stairway leading to it. The building is a large circular one with a single spire that sits atop it. The building is the center of the islands illusionary defence system and has an altar that can control them.