The district is in the Khian Sa basin, which is crossed by the Tapi River, which also forms part of the eastern boundary of the district. The area of the district is mostly used for palm farming or rubber plantations, while along the river are swamps like the Nong Thung Thong swamp.
The district was formed as a minor district (king amphoe) on 15 December 1970, splitting the two tambons Khian Sa and Phuang Phromkhon from Ban Na San District.[1] On 1 April 1974 it was elevated to full district status.[2]
Administration
The district is divided into five sub-districts (tambons), which in turn are further subdivided into 52 villages (mubans). Khian Sa has township status (thesaban tambon), covering parts of tambon Khian Sa. Each of the tambons is administered by a tambon administrative office (TAO).