 During the 1930s, Kōriyama was noted a center for military equipment production.It was thus a target for American bombers during World War II, and the city was subject to three large-scale air raids during the war.From 1954–1955, Kōriyama expanded by annexing the town of Otsuki and portions of the villages of Tomita and Iwae, and in 1965 annexed the villages of Nishida and Nakata.