Jeongju

Jeongju lies south of Hamhung, where the mountains of northeastern Korea descend towards the coastal plain. Ridges rising towards the Nangnim range enclose the western country, while lower ground opens towards the sea. Long contested between Goryeo and the Jurchens, this was a place of walls and guarded approaches. In 1041, Goryeo built a fortress and gate here, naming the strongpoint Jeongju and placing it under a defence commissioner.

Mongol expansion brought the region under Yuan authority, but King Gongmin recovered it in 1356 when Goryeo dismantled the Ssangseong administration. Jeongju became the seat of a protectorate, retaining its military importance under the succeeding Joseon dynasty. In 1413, King Taejong renamed it Jeongpyeong to distinguish it from the other Jeongju in Pyeongan. Its magistrate combined civil government with military duties within the Hamhung defence command, preserving the frontier responsibilities of this eastern stronghold.