Asan is a city in South Chungcheong Province, South Korea. It borders the Seoul Metropolitan Area to the north. Asan has a population of approximately 300,000Asan is known for its hot springs and is a city of spas.Asan has grown into the neighboring village, Onyang-dong, which is also known for its hot springs.Asan should not be confused with Ansan, in Gyeonggi Province.