Hongju, the former name for Hongseong which is on a spotlight for its candidacy for the state capital of Chungnam province, is said to have its history of administrative existence at the earliest since the tenth century, much later than other places. This paper looks into Hongju regarding its existence as an administrative unit and the foundation of its regional symbol, Hongju citadel. To briefly summarize the conclusion of the study: Firstly, the emergence of Hongju as an administrative unit was during the Unified Silla period which is obviously earlier than the previously said Koryo period. ‘Haepung,’ the name of provincial name of Hongju, seems to be the administrative name during that period. Secondly, the Buddhist sculpture of Singyeongri in the Yongbong Mountain appears to be built in the early Koryo period testifies to the development of Hongju during the late period of Silla and the early period of Koryo. The sponsor of the construction of the Buddhist sculpture seems the then influential local power, Geungjun. Thirdly, it is presumed that Hongju citadel is founded in the early part of Koryo. In comparison with other citadels built in the fifteenth century around the Sejong’s reign, Hongju citadel was dated much earlier. Hongju citadel is a stone-built of the early Koryo period expanded on the earth-built of the late Silla and early Koryo period.