Nakhon Sawan Province, also known as Pak Nam Pho is where the rivers of Ping, Wang, Yom, and Nan converge and form the Chao Phraya River, the most important waterway of Thailand. Nakhon Sawan is in the lower northern part of the country between the North and the Central Region. It is regarded as the doorway to the North and it is the hub of transportation in the Lower North.