Nonthaburi is one of the central provinces (changwat) of Thailand, established by the Act Establishing Changwat Samut Prakan, Changwat Nonthaburi, Changwat Samut Sakhon and Changwat Nakhon Nayok, Buddhist Era 2489 (1946), which came into force on 9 May 1946 (Thursday).

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.