Usanseong Fortress dating from the Baekje Period has been designated as Chungcheongnam-do Monument No. 81. Its height ranges from 3m to 7m and extends 965m from Eumnae-ri through Songbang-ri to Baekcheon-ri. The fortress was built along the 2 peaks and valleys of Usan Mountain.
Majority of the fortress, which is nearly 6m wide, was built with stones and filled with soil. The fortress mostly consists of natural rocks in dimensions of 30cm x 20cm and 40cm x 20cm. In the east and north parts of the fortress, the original structure has been preserved, based on which we can speculate about the fortress construction techniques implemented in the Baekje Period.
There are three gates along the fortress, and it is believed that the south gate served as the main gate. Artifacts excavated from the fortress site including earthenware dates back to the Baekje and Joseon periods. Usanseong Fortress, located near the downtown of Cheongyang, attracts numerous tourists with the Stone Statue of Three Standing Buddha (Treasure No. 197)" and Three-story Stone Pagoda (Cultural Property Resource No. 148).