Changhua County is the smallest county on the main island of Taiwan by area, and the fourth smallest in the country. With a total population of 1.24 million, Changhua County is the most populous county in the Republic of China. Its capital is Changhua City and it is part of the Taichung–Changhua metropolitan area.

Changhua, officially known as Changhua City, is a county-administered city and the county seat of Changhua County in Taiwan Province of the Republic of China. For many centuries the site was home to a settlement of Babuza people, a coastal tribe of Taiwanese aborigines. Changhua city is ranked first by population among county-administered cities. It is part of the Taichung–Changhua metropolitan area, which is the second largest in Taiwan.