Also known as: Kameyama Castle (亀山城), Horai Castle (蓬莱城)

The original fortifications of Marugame Castle were built by the Nara Clan during the Muromachi Period. During the Sengoku Period, Ikoma Chikamasa, daimyo of Sanuki Province (present-day Kagawa Prefecture, made it his residence. He later turned the castle over to his son Ikoma Kazumasa when he built Takamatsu Castle in 1597.