Wiang Ko Sai National Park
อุทยานแห่งชาติเวียงโกศัย
IUCN category II (national park)
Columnar basalt formations in park
Location within Thailand
Location	Lampang and Phrae Provinces
Coordinates	17°56′N 99°33′E / 17.93°N 99.55°E / 17.93; 99.55[1]
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.

Wiang Kosai National Park, with an area of 256,115 rai ~ 410 square kilometres (160 sq mi)^[2] is located in one of the mountain chains of the Phi Pan Nam Range, with the highest peak, Doi Mae Tom, reaching 1,267 m. The sources of many rivers, such as Mae Koeng, Mae Chok, Mae Sin and Mae Pak, are in these mountains.^[3] The park has two famous waterfalls, Mae Koeng Luang and Mae Koeng Noi, as well as the Mae Chok hot spring.^[4]

The mountains are largely covered with dry evergreen and mixed deciduous forest. The park used to be one of the few protected areas in Thailand where Asian elephants roamed in their natural habitat; formerly Tigers were also abundant in the mountains, but there have been no sightings in recent years.^[5] Currently animals in the park area include the Indian Muntjac, the Tree Shrew and the Indochinese Flying Squirrel.

• List of national parks of Thailand
• List of Protected Areas Regional Offices of Thailand

• Wiang Kosai National Park - Thaiforestbooking