The Yai River is a river of

Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is b ...

. It is a tributary of the

Pa Sak River The Pa Sak River ( th, แม่น้ำป่าสัก, , Pronunciation is a river in central Thailand. The river originates in the Phetchabun Mountains, Dan Sai District, Loei Province, and passes through Phetchabun Province as the back ...

, part of the Chao Phraya River basin.

See also