 A part of the town of Hongō (locality of Oya) (from Ōnuma District) was merged into Aizuwakamatsu on April 1, 1955.Aizuwakamatsu further expanded by annexing the village of Kitaaizu (from Kitaaizu District) on November 1, 2004 and the town of Kawahigashi (from Kawanuma District) on November 1, 2005.Aizuwakamatsu has a mayor-council form of government with a directly elected mayor and a unicameral city legislature of 29 members The city contributes four members to the Fukushima Prefectural Assembly.