Gongsanseong Fortress of Baekje

Gongsanseong Fortress was built to protect Ungjin (now Gongju City in Chungcheongnam-do), which was the capital of Baekje for 538 years and five generations until 16 (the 5th year of King Seong's reign), when the capital was moved to Buyeo. It is a mountain fortress built in the Baekje style, encircling the peak of Mt. Gongsan, 64 meters above sea level, to its western peak.

The circumference of the castle is 2450 meters, approximately 800 meters east to west, and 400 meters north to south, and stone walls remain on all four sides. When it was first built, it was an earthen castle, but during the Joseon Dynasty it was rebuilt into the stone castle that it is today.

From the ticket booth, a short walk up the slope leads to Geumseoru, the west gate of Gongsanseong Fortress. Within the fortress, there are Ssangsujeong, home to two zelkova trees that are reminiscent of the story of King Injo (1623-1649), who took refuge in Gongsanseong Fortress for a time during the Yi Seok Rebellion of the Joseon Dynasty; Ssangsujeong Historic Site Monument, with an inscription recording the 2 days King Injo spent fleeing from the Yi Seok Rebellion; and Jinnamul, the south gate, which was built when the fortress was remodeled from earthen to stone in the early Joseon Dynasty and served as the main gate through which visitors could enter and exit the city of Gongju. In front of this building is the believed site of the royal palace of Baekje.

Geumseoru

Gongsanseong Fortress, which has many other relics from various eras, was called Ungjinseong Fortress during the Baekje period, but has been called Gongsanseong since the Goryeo period and is designated as Historic Site No. 12.