In the early 20th Century, the criteria of being a provincial municipality, as stated in Laws on the City Formation (市組織法), included being the provincial capital as well as having a population of over 200,000, or over 100,000 if the city had a particular significance in politics, economics and culture. After moving to Taiwan, where many cities considered to be insignificant had large populations, the Republic of China government raised the limit to 500,000 in 1981 in the Scheme on the Local Rules in Various Counties and Cities of Taiwan Province (臺灣省各縣市實施地方自治綱要). It was later raised again to 600,000.
There are currently 5 provincial municipalities administered by the Republic of China: Keelung, Hsinchu, Taichung, Chiayi, and Tainan.
There were originally four more: Taipei and Kaohsiung were upgraded to direct-controlled municipalities, while Changhua and Pintung were lowered to county-controlled cities. Chiayi and Hsinchu were temporarily lowered to county-controlled cities as well until 1982.
In the Mainland, provincial cities are directly under the jurisdiction of the provincial government and are equal in status with prefecture-class cities (the two terms are used interchangeably). In actuality, they can come under the governance of prefecture-class cities (bringing them to similar status with to county-level cities).