Genosha is an island that once served as a base for the Brotherhood of Mutants.
Located a few miles from the coast of the eastern seaboard, Genosha was an island of relatively small size, making it practically undetectable. Appearing rather nondescript from the outside, inside, the island was heavily fortified by Magneto. The interior of the island was reinforced with steel girders, heavy titanium furnishings, and metallic walkways that could be manipulated by the master of magnetism. The base was also well equipped, providing several accommodations for the Brotherhood and it's members. Such areas included lodging, a mechanical workshop, a helipad, a boat dock, an interrogation room, and holding cells for prisoners such as Senator Kelly. The island also contained a private sanctuary for Magneto, where he would often plot his schemes. As seen in the Magneto prequel comic, the sanctuary also contained a room equipped with several televisions that lined the walls; here, Magneto would monitor important news broadcasts.