According to most historians, the ancient town of Kanchanaburi was located near Ban Lat Ya, a small village situated approximately 16 kilometers north of the present town. The site was repeatedly recorded in Thai history as an invasion route which the Burmese used to enter Thai Kingdoms.

Kanchanaburi, which has mostly mountainous terrain, covers an area of approximately 19,473 square kilometers and is the third largest province in Thailand after Chiang Mai and Nakhon Ratchasima. Situated approximately 129 kilometres west of Bangkok, Kanchanaburi shares a border with Myanmar to the west, Tak and Uthai Thani Provinces to the north, Suphan Buri and Nakhon Pathom Provinces to the east, and Ratchaburi Province to the south.