Flows through Pai District, Pang Ma Pha District, and Mueang Mae Hong Son District in Mae Hong Son Province, before draining into the Salween River in Kayin State, Myanmar. Its source is located in the Thanon Thongchai mountain range and the Dan Lao mountain range in Pai District. The river is approximately 180 kilometers long.

The location of the Dan Lao mountain range is in Pai District, Mae Hong Son Province, Thailand. The range forms part of the natural border between Thailand and Myanmar and is known for its rugged terrain and scenic beauty.