On 12 May 1969, the minor district (king amphoe) Chiang Mun was established as a subordinate of Pong district, consisting of the two tambons Chiang Muan and Sa.
On 12 May 1969, the minor territorial division (king amphoe) Chiang Mun was established as a subordinate entity of Pong district, encompassing the two villages Chiang Muan and Sa.