Чаупхрая
The Chao Phraya River system is the main river system of Thailand, as its basin defines much of the region of central Thailand. The Chao Phraya River begins at the confluence of the Ping and Nan Rivers at Nakhon Sawan (also called Pak Nam Pho) in Nakhon Sawan Province. It then flows from north to south for from the central plains through Bangkok to the Gulf of Thailand. The Chao Phraya River Catchment area is approximately 17,270 km2.