During the reign of Emperor Shōmu, a system of provincial Buddhist temples or Kokubun-ji (国分寺) were established,[2] including one at Saijō in what is today Higashihiroshima.
In 1974, Higashihiroshima was created from the merger of four neighboring towns—Saijō, , Hachihonmatsu, Shiwa, and Takaya. In 2005, more towns were merged into the city—Kurose, Kōchi, Toyosaka, Fukutomi and Akitsu.