The fort, built in the period of Koguryo Kingdom (B.C. 277-A.D. 668) and reinforced on several occasions, consists of four walls -- Main Walls, Yaksan Walls, Sin Walls and Puk Walls.

Yaksan and Main walls were built in the period of Koguryo Kingdom, the Sin Walls in the southwestern part of Main Walls in 1683 and Puk Walls in the northwestern part of Main Walls in 1684.

Main Walls is 14 kilometers in circumference, Yaksan Walls nearly 1 km, Sin Walls about 3 kms and Puk Walls 2 kms. And the height of the walls is 6-7 meters. In the fort there were three streams and 50 wells.

The fort tells a lot of stories about the struggles waged by the Korean people against the foreign invaders coming from the north.