Hongseong County is a county in South Korea, and the capital of South Chungcheong Province. The current governor is Lee Yong-log. The original name of the city is Hongju.

South Chungcheong Province, also known as Chungnam, is a province of South Korea in the Hoseo region in the southwest of the Korean Peninsula. South Chungcheong borders the provinces of Gyeonggi to the north, North Chungcheong, Sejong Special Self-governing City, and Daejeon Metropolitan City to the east, and North Jeolla to the south.