| Official Name: | Lahan Sai |
| Native Name: | ละหานทราย |
| Native Name Lang: | th |
| Settlement Type: | District |
| Subdivision Type: | Country |
| Subdivision Name: | Thailand |
| Subdivision Type1: | Province |
| Subdivision Name1: | Buriram |
| Subdivision Type2: | Seat |
| Subdivision Type3: | Tambon |
| Subdivision Type4: | Muban |
| Established Title: | District established |
| Population Total: | 70825 |
| Population As Of: | 2008 |
| Blank Name Sec1: | Postal code |
| Blank Info Sec1: | 31170 |
| Blank Name Sec2: | Geocode |
| Blank Info Sec2: | 3106 |
| Timezone: | ICT |
| Utc Offset: | +7 |
| Coordinates: | 14.4117°N 102.86°W |
Lahan Sai (Thai: ละหานทราย, in Thai pronounced as /lā.hǎːn sāːj/) is a district (amphoe) in the southern part of Buriram province, northeastern Thailand.
Lahan Sai area was originally part of Nang Rong district. The area was fertile and covered by dense forest, so people from neighboring districts moved to establish new village there. When the community grew bigger, the government created a minor district (king amphoe) on 1 January 1961[1] to make it more comfortable for the citizen to reach public services. The new district covered tambons Lahan Sai and Pakham. It was upgraded to a full district on 17 July 1963.[2]
Lahan Sai means "plain fertile width hog deer" (Axis porcinus).
Neighboring districts are (from the southwest clockwise) Ta Phraya of Sa Kaeo province, Non Din Daeng, Pakham, Nang Rong, Chaloem Phra Kiat, Prakhon Chai, and Ban Kruat of Buriram Province. To the southeast it borders the provinces of Banteay Meanchey and Oddar Meancheay of Cambodia.
The Sankamphaeng Range mountainous area is in the southern section of this district.
The Lahan Sai District's motto is "The Lung Pu Suk so sacred, city of horticulture and farm plants, many of silk, beautiful of Hin-Lum (Rock hole), many of river basin, Lanan Sai is border city."
The district is divided into six sub-districts (tambons), which are further subdivided into 95 villages (mubans). Lahan Sai is a sub-district municipality (thesaban tambon) which covers parts of tambons Lahan Sai. Ta Chong, Samrong Mai, and Nong Waeng are sub-district municipalities which each cover the complete same-named sub-district. The non-municipal parts of Lahan Sai and the sub-districts Nong Takhrong and Khok Wan each have one tambon administrative organization (TAO).
| No. | Name | Thai | Villages | Pop. | |
|---|---|---|---|---|---|
| 1. | Lahan Sai | ละหานทราย | 27 | 12,346 | |
| 3. | Ta Chong | ตาจง | 22 | 15,575 | |
| 4. | Samrong Mai | สำโรงใหม่ | 13 | 12,068 | |
| 7. | Nong Waeng | หนองแวง | 11 | 15,676 | |
| 10. | Nong Takhrong | หนองตะครอง | 12 | 8,011 | |
| 11. | Khok Wan | โคกว่าน | 10 | 7,149 |