This study examines the spatial structure of Jeju-eupseong (Town-castle) in the Joseon Dynasty. The spatial structure of Jeju-eupseong has distinctive features and regional characteristics that are substantially different from typical eupseong in inland regions. This is mainly attributed to the geographical characteristics of the island and the administrative system with strengthened military functions. Jeju-eupseong displays a distinctive layout of major buildings and road system with a plaza located in its center in comparison with the ones found in inland regions. Gwandeokjeong Plaza in Jeju-eupseong served as the center of Jeju’s politics, administration, and culture during the Joseon Dynasty, and it, in the modernization period, has become an open public space in the heart of Old Downtown used for community gatherings. Therefore, this study aims to explore the historical background and distinctive spatial structure of Jeju-eupseong in comparison with eupseong in other parts of Korea. Moreover, the study examines the characteristics of Gwandeokjeong as a plaza that has not been dealt with in other studies of eupseong.

The following research of the road network of Jeju-Eupseong during Daehan Empire period has a twofold purpose: to study some characteristics of the road network at that time; and, to restore it to the original form of that period before a newly constructed road, called Shinjakro, has been established. As an attempt to trace the old shape of Jeju-Eupseong, this study analyzed some historical factors based on the first land cadastral map which was made in 1914, including outskirts of Jeju-Eupseong; such as castle itself, castle gate, road, bridge, lots of land, etc. Then this study also tried to restore the old road network of Jeju-Eupseong, through finding the original land-lot shape in the land cadastral map. There was five Shinjakro made between 1914 and 1917. The road network before then was composed of the double east-west axes and the single north-south axis. These axes was connected to some important place of the inside of Jeju-Eupseong; such as castle gates, fountains, Gaek-sa, etc. There were many branch lines between these main axes at about 80-120m intervals. Also there was an outer road along the outer wall of castle, connected with each castle gates. Especially, the north-west axis was the baseline which divided into two large parts, a government office area and non-government area (housing and commercial street for the people). Finally, this paper examines that the road network of Jeju-Eupseong was the true result for the efficient function of the city, especially considering natural geographical conditions and environment of living of that time.