Thai local governments are classified into two main categories; general and specific. In the general form, there are three types of local authorities located throughout all seventy-five province save Bangkok. They are 1 Provincial Administrative Organization (seventy-five units), 2 Municipality (1.136 units), and 3 Sub-district or Tambon Administrative Organization ( 6.740 units). In the specific form there are two special units of local governments governing specific areas; namely, Bangkok Metropolitan Administration (BMA) and Pattaya City.
The three general forms of local governments are divided into two tiers. The lower-tier governments, municipality and TAO, Function as a single operating unit. which is very close to local residents, providing local public services within their defined territory, While municipalities are located in urbanized areas, TAOs are mostly established in less-developed rural communities. By Contrast, PAO is the upper-tier local government which covers an entire province and is responsible for administering local public services at the provincial level as well as for working In development projects that need collaboration among several municipalities or TAOs within the provincial territory. In other words, the service functions that cross the boundaries of any single municipality or TAO are held by PAO.