Kanchanaburi is a province in western Thailand, located about 128 km (80 mi) west of Bangkok. It is bordered by the provinces of Nakhon Pathom to the east, Ratchaburi to the north, and Prachuap Khiri Khan to the south. The province has an area of 6,772 km² (2,619 sq mi) and a population of 1,093,871 (2015).
The provincial capital is Kanchanaburi town. The province is home to Erawan National Park, Sai Yok National Park, and Thungyai-Huai Kha Khaeng Wildlife Sanctuaries. The province is famous for its World War II–era bridge over the River Kwai, and the Death Railway which was built during the Japanese occupation of Thailand.