In the early of the Rattanakosin era at the end of the 18th century, Mr. Phumi led the people from Mueang Nakhon Thai district, a subordinate of Phitsanulok, to establish their new town in this area.

The king promoted him to be Muen Aram Kamhaeng and Luang Phichit Songkhram later, the first governor position of Khon San.

On 16 August 1958 it was again separated from Phu Khiao and became a minor district (king amphoe), then containing the three tambons Khon San, Nun Khun, and Thung Phra.

The Chulabhorn Dam creates an artificial lake on the Nam Phrom River, covering about 12 km2.

[3] Khon San is divided into eight subdistricts (tambons), which are further subdivided into 85 administrative villages (mubans).