Lạc Sơn district
Lạc Sơn district 
    Huyện Lạc Sơn Hwiḙ̂n La̭c Xơn  | |
|---|---|
| Nickname(s):  "Mother of the Water" (Mế Nước)  | |
Interactive map outlining Lạc Sơn rural district.  | |
Hổ hamlet ("tiger") of Yên Nghiệp commune in 2022.  | |
| Coordinates: 20°30′00″N 105°30′00″E / 20.500°N 105.500°E | |
| Country | Vietnam | 
| Region | Northwest | 
| Province | Hòa Bình | 
| Existence | XIX century to August 30, 2025 | 
| Central hall | Vụ Bản township | 
| Subdivision | 1 township and 23 rural communes | 
| Government | |
| • Type | Rural district | 
| Area | |
 • Total  | 580 km2 (220 sq mi) | 
| Population  (2019)  | |
 • Total  | 136,652 | 
| • Density | 240/km2 (610/sq mi) | 
| Time zone | UTC+7 (Indochina Time) | 
| ZIP code | 3600  | 
| Website | Lacson.Hoabinh.gov.vn Lacson.Hoabinh.dcs.vn  | 
Lạc Sơn (Mươ̒ng: Hwiḙ̂n La̭c Xơn, Kinh: Huyện Lạc Sơn) is a former rural district of Hòa Bình province in the Northwest region of Vietnam.