Chanthaburi is one of seven provinces (changwat) in eastern Thailand, on the border with Battambang and Pailin of Cambodia, on the shore of the Gulf of Thailand. Neighbouring provinces are Trat in the east and Rayong, Chonburi, Chachoengsao, and Sa Kaeo to the west and north.

The provinces of Thailand are administrative divisions of the government of Thailand. The country is divided into 76 provinces proper, with one additional special administrative area. They are the primary local government units and act as juristic persons. They are divided into amphoe (districts) which are further divided into tambon, the next lower level of local government.