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.
In the context of administrative divisions in Thailand, on 12 May 1969, the smaller regional unit (king amphoe) Chiang Mun was created as a subdistrict of Pong district, comprising the two villages Chiang Muan and Sa.