Ch'ŏngsansŏng

Ch'ŏngsansŏng was a Baekje-era Korean fortress in Buyeo County, South Chungcheong Province, South Korea. On January 21, 1963, its former location was declared Historic Site of South Korea No. 59.
It was possibly built around 605. It is connected to the Naseong City Wall, and was possibly built around the same time as that wall. The fortress had two sets of walls, an inner wall with circumference and outer wall with circumference. It was on top of a small mountain. It is mentioned in the Samguk sagi. The only significant remains of the fortress that still exist are earthen ramparts.