The minor district (king amphoe) Phon Sai was established on 16 November 1976, when the two tambons, Phon Sai and Samkha, were split off from Suwannaphum district.
The minor district (king amphoe) Phon Sai was founded on 16 November 1976, when the two tambons, Phon Sai and Samkha, were separated from Suwannaphum district.