Ehime Prefecture is a prefecture in northwestern Shikoku, Japan. The capital is Matsuyama.
Until the Meiji Restoration, Ehime prefecture was known as Iyo Province. Since before the Heian-era, the area was dominated by fishermen and sailors who played an important role in defending Japan against pirates and Mongol invasions.
After the Battle of Sekigahara, the Tokugawa shogun gave the area to his allies, including Kato Yoshiaki who built Matsuyamajo Castle, forming the basis for the modern city of Matsuyama.
The name Ehime comes from the Kojiki and means "beautiful maiden."
Located in the northwestern part of Shikoku, Ehime faces the Seto Inland Sea to the north and is bordered by Kagawa and Tokushima in the east and Kochi in the south.
The prefecture includes both high mountains in the inland region and a long coastline, with many islands in the Seto Inland Sea. The westernmost arm of Ehime, the Sadamisaki Peninsula, is the narrowest peninsula in Japan.