A county,[I] constitutionally known as a hsien,[1] is a de jure second-level administrative division unit in the Republic of China (Taiwan).

Hsien have existed since the Warring States period, and were set up nation-wide by the Qin dynasty.

Government below the county level was often undertaken through informal non-bureaucratic means, varying between dynasties.

The first administrative divisions named "county" (縣) was first established in 1661 by the Kingdom of Tungning.

With the increase of Han Chinese population in Taiwan, the number of counties also grew by time.

[5] Their roman spellings were also changed to reflect the official language shift from Japanese to Mandarin Chinese, but characters remained the same.

In late 1949, the government of the Republic of China lost the Chinese Civil War and was relocated to Taipei, Taiwan.