| Pai River | |
| Map: | Topography of northern Thailand.png |
| Subdivision Type1: | Country |
| Subdivision Name1: | Thailand, Burma |
| Subdivision Type2: | State |
| Subdivision Name2: | Mae Hong Son Province (Thailand), Kayah State (Burma) |
| Length: | 180km (110miles) |
| Source1 Location: | Daen Lao Range, Pai District, Mae Hong Son Province, Thailand |
| Source1 Coordinates: | 19.45°N 98.4889°W |
| Source1 Elevation: | 1170m (3,840feet) |
| Mouth: | Salween |
| Mouth Location: | Punghsa-se, Kayah State, Burma |
| Mouth Coordinates: | 19.1458°N 97.5444°W |
| Mouth Elevation: | 111m (364feet) |
The Pai River (in Thai pronounced as /mɛ̂ːnáːm paːj/;) is a river that originates in the mountains of the Daen Lao Range, Pai District, Mae Hong Son Province, Thailand. The river flows first in a north-south direction and then in an east-west direction down to Mueang Mae Hong Son District and across the Thai/Burmese border. The river tributes the Salween River in Kayah State, Burma. It is 180km (110miles) long.
Its name in the Lanna language (50px) means "male elephant", comparable to the word "Plai" in the central Thai language. There is a story that in 1477 during the reign of King Tilokaraj, who was the ruler of Lanna Kingdom. He ordered his cousin Prince Si Chaiya to attack Ban Don. Meanwhile, one of his white elephants fled, he ordered the soldiers to find and found that it was swimming in this river.[1]
Pai River is popular for whitewater rafting.[2] Rapids on the river vary from class I to class IV on the International Scale of River Difficulty and everything in between. Other than that The Pai River offers a scenic view of mountain forest and many choose to camp along the quiet river banks.