The main wall at Namhan Mountain Fortress is the central wall, excluding the three outer walls: Bongamseong, Hanbongseong and Sinnamseong. The main wall can be described as overlapping the areas where Jujang Fortress stood in Unified Silla and where the wall was rebuilt during the reign of Joseon King Injo. The Joseon Period Namhan Mountain Fortress can be divided into the Southeastern and Northwestern Walls, with the South Gate and North Command Post as the dividing points. Yi Seo was in charge of the overall construction project. The Southeastern Wall was constructed by army troops under the direction of General Yi Hoe, while the Northwestern Wall was built by monk soldiers led by their commander, Great Monk Byeokam Gakseong.
The wall surrounds the outer rim of Mt. Cheongryang, which peaks at 497 meters. (From the southwest corner), it winds around the contour of the mountain at about 480 meters, then turns north, following a virtually straight ridgeline that drops to about the 450m elevation, where the West Gate is located. From here, the wall rises 56m and juts out 24.6m to form the northeast corner. Turning east, the wall reaches the base of a major north-south ridge. The Yeonjubong(Peak) Ongseong is built along this ridge.