Lang Suan was originally a mueang reporting directly to Bangkok. During the Thesaphiban reforms at the end of the 19th century it was put under monthon Chumphon. On 29 April 1917 the district's name was changed from Mueang Lang Suan to Khan Ngein (ขันเงิน).[1] On 1 April 1932 the province was abolished and its districts were incorporated into Chumphon province.[2] On 14 November 1938 the district's name was changed to Lang Suan (หลังสวน).[3]
The district is divided into 13 sub-districts (tambons), which are further subdivided into 147 villages (mubans). The town (thesaban mueang) Lang Suan includes the tambon Lang Suan and parts of Khan Ngoen, Pho Daeng, Laem Sai, and Wang Tako. The sub-district municipality (thesaban tambon) Paknam Lang Suan includes tambon Pak Nam. There are a further 12 tambon administrative organizations (TAO).
^"ประกาศเรื่องเปลียนชืออำเภอ" [Notice of changing district name] (PDF). Royal Thai Government Gazette. 34: 40–68. 29 April 1917. Archived from the original(PDF) on November 7, 2011. Retrieved 15 November 2019, page 51{{cite journal}}: CS1 maint: postscript (link)