# Ōmishima Island

Ōmishima Island (大三島, Ōmishima) 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 Washigatozan (鷲ヶ頭山) at an altitude of 437 m (1,434 ft).

## 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 Miyaura [ja] is located. The island's Utena Dam reservoir is the primary freshwater source for Ōmishima itself and the nearby Hakata.

## History

* 1541 - Tsuruhime fights Ōuchi Yoshitaka fleet
* 1874 - post office established
* 1979 - Ōmishima bridge [ja] connecting to Ehime Prefecture complete
* 1999 - Tatara Bridge connecting to Hiroshima Prefecture complete
* 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

Climate data for Ōmishima (1991−2020 normals, extremes 1978−present) :
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Record high °C (°F) | 16.0 (60.8) | 20.2 (68.4) | 25.4 (77.7) | 27.9 (82.2) | 30.4 (86.7) | 33.7 (92.7) | 38.0 (100.4) | 37.4 (99.3) | 36.1 (97.0) | 31.9 (89.4) | 24.1 (75.4) | 20.4 (68.7) | 38.0 (100.4) |
| Mean daily maximum °C (°F) | 9.6 (49.3) | 10.2 (50.4) | 13.4 (56.1) | 18.6 (65.5) | 23.2 (73.8) | 26.1 (79.0) | 30.0 (86.0) | 32.0 (89.6) | 28.3 (82.9) | 22.8 (73.0) | 17.2 (63.0) | 12.0 (53.6) | 20.3 (68.5) |
| Daily mean °C (°F) | 5.5 (41.9) | 5.6 (42.1) | 8.4 (47.1) | 13.1 (55.6) | 17.6 (63.7) | 21.3 (70.3) | 25.3 (77.5) | 26.8 (80.2) | 23.4 (74.1) | 18.0 (64.4) | 12.5 (54.5) | 7.7 (45.9) | 15.4 (59.8) |
| Mean daily minimum °C (°F) | 1.3 (34.3) | 1.1 (34.0) | 3.4 (38.1) | 8.0 (46.4) | 12.7 (54.9) | 17.6 (63.7) | 22.0 (71.6) | 23.2 (73.8) | 19.7 (67.5) | 13.8 (56.8) | 8.2 (46.8) | 3.4 (38.1) | 11.2 (52.2) |
| Record low °C (°F) | −5.9 (21.4) | −6.2 (20.8) | −4.4 (24.1) | −1.5 (29.3) | 3.6 (38.5) | 9.6 (49.3) | 15.5 (59.9) | 15.6 (60.1) | 11.1 (52.0) | 5.5 (41.9) | −1.3 (29.7) | −3.5 (25.7) | −6.2 (20.8) |
| Average precipitation mm (inches) | 40.8 (1.61) | 54.0 (2.13) | 89.5 (3.52) | 98.0 (3.86) | 116.2 (4.57) | 186.3 (7.33) | 194.6 (7.66) | 93.5 (3.68) | 133.4 (5.25) | 96.3 (3.79) | 66.0 (2.60) | 50.1 (1.97) | 1,218.6 (47.98) |
| Average precipitation days (≥ 1.0 mm) | 5.3 | 6.7 | 9.0 | 8.9 | 8.7 | 11.1 | 9.4 | 6.7 | 8.8 | 7.3 | 6.4 | 6.0 | 94.3 |
| Mean monthly sunshine hours | 146.1 | 151.2 | 182.0 | 200.2 | 214.7 | 157.1 | 201.2 | 233.9 | 171.2 | 180.4 | 159.2 | 144.3 | 2,141.6 |
| Source: JMA ||||||||||||||

## 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 factory
* Historical and marine museum
* 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