Bueng Boraphet is the largest freshwater swamp and lake in central Thailand. It covers an area of 224 km2 east of Nakhon Sawan, south of the Nan River close to its confluence with the Ping River. This swamp can be seen from the train window between Bueng Boraphet and Thap Krit stations on the Northern railway line.

Central Thailand is one of the regions of Thailand, covering the broad alluvial plain of the Chao Phraya River. It is separated from northeast Thailand (Isan) by the Phetchabun mountain range. The Tenasserim Hills separate it from Myanmar to the west. In the north it is bounded by the Phi Pan Nam Range, one of the hilly systems of northern Thailand. The area was the heartland of the Ayutthaya Kingdom, and is still the dominant area of Thailand, containing as it does, the world's most primate city, Bangkok.