Cheonan is a city located in South Korea. It serves as the largest and most densely populated city within the South Chungcheong Province.
The city ranks as the third largest in the Hoseo region, following Daejeon and Cheongju. Geographically, Cheonan borders Gyeonggi Province to the north, North Chungcheong Province to the east and southeast, Sejong to the south, and the cities of Asan and Gongju to the west and southwest.