Marugame is a port city in western Kagawa Prefecture on Shikoku, located just west of the Seto Ohashi Bridge which connects Shikoku to Japan's main island of Honshu. The second largest city in the prefecture, Marugame includes many of the Shiwaku Islands, a historically important island group that lies just off the coast of the city. The Shiwaku Islands include Honjima Island, the former governing center of the island group. Several of the islands serve as festival venues for the Setouchi Triennale.