Chao Phraya River It is an important river in Thailand. caused by the combination of two main rivers from the north, namely the Ping River and the Nan River. by converging in front of the dam in the city at Pak Nam Pho Subdistrict Mueang Nakhon Sawan District Nakhon Sawan Province will see the differences of the two rivers clearly, that is, the Nan River will be quite red color. ..