is the largest island in the Geiyo Islands chain, and the westernmost island on which Japan's Nishiseto Expressway, which links Honshu and Shikoku via a number of islands, runs. It is located in the Seto Inland Sea. The island's highest peak is at an altitude of .
Population The population as of the 2020 census was 4,963 - 2,299 men, and 2,264 women.
Geography Ōmishima is kidney-shaped and together with Ōsakikamijima on the west encloses the calm bay of Utena, where the primary seaport of is located. The island's Utena Dam reservoir is the primary freshwater source for Ōmishima itself and the nearby Hakata.
Nature Originally, the island had many bald mountains and little vegetation. Most of the forests that exist today have been artificially planted since the Meiji period. It is believed that in prehistoric times, the vegetation was dominated by ubame oak (Quercus phillyraeoides), tobira (Pittosporum tobira), and camphor trees (Camphora officinarum). Even today, old camphor and ubame oak trees remain at the shrine, and the "Camphor trees of Oyamazumi Shrine" in particular are a group of camphor trees in a primeval forest grove and have been designated a national natural monument.
History 1541 - Tsuruhime fights Ōuchi Yoshitaka fleet 1874 - post office established 1979 - connecting to Ehime Prefecture complete 1999 - Tatara Bridge connecting to Hiroshima Prefecture completeTatara bridge at Honshū Shikoku Bridge Authority 16 January 2005 - several towns (including Ōmishima, Ehime) and villages on the island were merged into the city of Imabari, Ehime, along with towns and villages on other surrounding islands.
Climate
Transportation Ōmishima is connected to the mainland of Honshu and Shikoku islands by the bridges of the Nishiseto Expressway (Shimanami Kaidō). A ferry is also available from the island to Ōsakikamijima, Okamura Island and Ōkunoshima (Rabbit Island). Ōmishima Island is served by the national Route 317.
Attractions The salt factoryHakata no Shio Factory Historical and marine museumMuseum of Oomishima Ōyamazumi Shrine Toyo Ito Museum of Architecture, Imabari The entire Ōmishima Island is designated as a National Place of Scenic Beauty
Notable residents Shozo Fujita - historian Tsuruhime - priestess and warlord
External links Imabari city official site
See also Hyōtanjima
References This article incorporates material from Japanese Wikipedia pages 大三島 and 大三島町, accessed 13 September 2017