Nakhon Sawan is about 250 kilometres (160 mi) north of Bangkok, and marks the point of confluence of two of Thailand's major rivers, the Ping and the Nan.

These converge in Nakhon Sawan to form the Chao Phraya which flows south to Bangkok and out into the Gulf of Thailand.

Bueng Boraphet, east of Nakhon Sawan, is Thailand's biggest freshwater swamp.

It is located in a valley, thus resulting in some of the highest overnight lows in the country, often reaching 33 °C (91 °F) in the summer,[citation needed] and up to 43 °C (109 °F) in the day.

Nakhon Sawan lies on Route 1 (Phahonyothin Road), which runs from Bangkok through Ayutthaya and Saraburi before passing through Nakhon Sawan, then continues through Kamphaeng Phet, Lampang, and Chiang Rai until it reaches the border with Myanmar at Mae Sai.