Wiang Kosai National Park
| Wiang Ko Sai National Park | |
|---|---|
| อุทยานแห่งชาติเวียงโกศัย | |
Columnar basalt formations in park  | |
| Location | Lampang and Phrae Provinces | 
| Coordinates | 17°56′N 99°33′E / 17.93°N 99.55°E | 
| Area | 410 km2 (160 sq mi) | 
| Established | 1981 | 
| Visitors | 22,060 (in 2019) | 
| Governing body | Department of National Park, Wildlife and Plant Conservation | 
Wiang Ko Sai National Park (Thai: อุทยานแห่งชาติเวียงโกศัย) is a national park in Northern Thailand. It covers parts of the Wang Chin District of Phrae Province and Mae Tha, Thoen and Sop Prap Districts of Lampang Province.