Onpyeong-ri Hwanhae Jangseong

Designated as Jeju Special Self-Governing Province Monument No. 49-9, Onpyeong-ri Hwanhae Jangseong is a historic fortress site built along the coastline during the Joseon Dynasty to defend against foreign invasions. The walls stretch from the coastal area of Hadong, Onpyeong-ri, Seongsan-eup, to the boundaries of Sinsan-ri village. It is conveniently located near Onpyeong Port and marks the endpoint of Olle Trail Course 2.