| Sansui County | |
| Native Name: | 三穗县 |
| Native Name Lang: | zh-Hans |
| Postal Code: | 556500 |
| Postal Code Type: | Postal code |
| Settlement Type: | County |
| Pushpin Map: | Guizhou#Southwest China |
| Pushpin Label: | Sansui |
| Pushpin Map Caption: | Location of the seat in Guizhou |
| Subdivision Type: | Country |
| Subdivision Name: | China |
| Subdivision Type1: | Province |
| Subdivision Name1: | Guizhou |
| Subdivision Type2: | Autonomous prefecture |
| Subdivision Name2: | Qiandongnan |
| Seat Type: | County seat |
| Seat: | Bagong |
| Area Code: | 0855 |
| Area Total Km2: | 1035.8 |
| Population As Of: | 2010 |
| Population Density Km2: | auto |
| Population Total: | 155,671 |
| Coor Pinpoint: | Sansui government |
| Coordinates: | 26.953°N 108.6753°W |
| Timezone: | China Standard |
| Utc Offset: | +8 |
Sansui County is a county in eastern Guizhou province, China, bordering Hunan province to the east. It is under the administration of the Qiandongnan Miao and Dong Autonomous Prefecture and is one of the province's eastern gateways.
Sansui County is divided into seven towns and two townships:[1]
Sansui County is located in the east of Guizhou and the northeast of Qiandongnan Prefecture away from the provincial capital of Guiyang and away from the prefecture seat of Kaili. It ranges in latitude from 26° 47' to 27° 04' N and in longitude from 108° 32' to 109° 04' E, spanning a total area of . Bordering counties are Xinhuang (Hunan) to the northeast, Tianzhu and Jianhe to the southeast and southwest, and Zhenyuan to the north. The county is part of the Yuan River watershed, and there is a total of of rivers within its borders.
Sansui has a monsoon-influenced humid subtropical climate (Köppen Cfa), with chilly, damp winters, and hot, humid summers. The monthly daily average temperature ranges from 3.9°C in January to in July, while the annual mean is . More than half of the annual rainfall occurs from May to August, while the annual frost-free period typically lasts 290 to 300 days.
The county has one railway station, Sansui railway station.
The Three Arch Bridge (Longting Bridge) collapsed on 8 August 2024.[2]