Thailand is variably divided into different sets of regions, the most notable of which are the six-region grouping used in geographic studies and the four-region grouping consistent with the former administrative region grouping system used by the Ministry of Interior. These regions are the largest subdivisions of the country. In contrast to the provinces the regions have no administrative character, but are subdivisions used for statistical or other geographical purposes only.
The six-region system was developed in 1978 by the National Geographical Committee, which was appointed by the National Research Council. It divides Thailand into the following regions:
The four-region system divides the country into the following regions: