黄海北道
Taehung Castle is a mountain fortress of the early Goryeo period, located outside Kaesŏng, North Hwanghae Province, North Korea. Originally encompassing both Mts. Chŏnma and Songgo, the castle was first founded as a fortress for the defense of the capital, encircled by over 10 kilometers of stone walls. Today, many of the walls have become overgrown ruins.