 The villages of Ōkawa and Koizumi were created within Ōra District, Gunma Prefecture on April 1, 1889 with the creation of the municipalities system after the Meiji Restoration.Koizumi was elevated to town status on July 25, 1902.On March 31, 1957 Koizumi merged with the village of Ōkawa and was renamed Ōizumi.