It begins at the confluence of the Ping and Yom river at Nakhon Sawan[?] (also called Pak Nam Pho) in the Nakhon Sawan province. The Yom and its biggest confluent, the Nan river, flow nearly parallel from Phitsanulok[?] till Chumsaeng in the north of Nakhon Sawan province. The biggest confluent of the Ping is the Wang river which enters near Wang Chin.