Mikame-cho(38445) in Nishiuwa-gun, Akehama-cho(38461), Uwa-cho(38462), Nomura-cho(38463) and Shirokawa-cho(38464) in Higashiuwa-gun are merged, and Seiyo-shi(38214) is newly established.
三瓶町(38445)、明浜町(38461)、宇和町(38462)、野村町(38463)、城川町(38464)が合併し、西予市(38214)を新設