On April 1, 2004 all towns and villages in the former Higashiuwa District (dissolved by this merger) and Mikame from Nishiuwa District merged, forming the new city of Seiyo.
On August 1, 2004 the town of Kuma and the villages of Mikawa, Omogo, and Yanadani from Kamiukena District merged to form the new town of Kumakogen.
On January 16, 2005 the new city of Imabari was formed by the mergers of 11 towns and villages (all from OchiDistrict) and the old city of Imabari.