Located in the northern and western part of Jiuliancheng County, the site of ancient Jiuliancheng Castle has Yalu River in the east and Zhendong Mountain at its back. The castle is called Jiuliancheng because the nine big and small component castles are closely connected with each other. Four sites are well retained together with five gazebos. One site lies in the West Jiuliancheng County with a shape of square. It has two doors in the east and west, a 225-meter high wall in the south, and an earth wall of four meters in height. Various ancient wares of Liao, Jin, and Yuan dynasty unearthed in the castle, including porcelain, colored glaze pearls, brickbat pieces, large stone mortar, and cash of Song dynasty, prove that the castle used to be a site of ancient castle of the three dynasties.
Jiuliancheng Castle has a long history. Administrations in the castle were set up first in Jin dynasty with Posuo Office as a local governing body. Later the castle became a station of Inspection Department of Posuo Office in Yuan dynasty, and then had Zhenjiang County constructed here in Ming dynasty. Changdian Fortress Guerrilla Force was once moved into the castle which was considered as a place with military importance. In Ming and Qing dynasty, the castle is a key pass for trade and peaceful communication between China and DPRK.