Construction of Haenam Eupseong, the town's fortress wall, is estimated to have begun in 1437 and to have been substantially completed by 1469 (the first year of King Yejong's reign), when Jeongwollu, the fortress's southern gate tower, was finished. This construction coincided with a broader nationwide campaign under King Sejong to build fortress walls around coastal towns. During this period, every county facing the sea was expected to build defenses against Japanese pirate raids, and Haenam, sitting at the southernmost tip of the country, was no exception.
Sited on what tradition holds was a spot of excellent feng shui, this fortress produced, over the course of the Joseon dynasty, 192 local magistrates. What stands out is that the overwhelming majority of them were military officials rather than civil scholars. This suggests that Haenam functioned not merely as an administrative county but as a front line of coastal defense. It is no coincidence that centuries later, ahead of the Battle of Myeongnyang, Admiral Yi Sun-sin relocated the Joseon navy to Usuyeong, the Right Naval Command post, in this same county — a decision inseparable from Haenam's geographic and military standing. The fortress that went unremarked in peaceful times would, in the crisis of the 1597 Japanese invasion, finally reveal why it had been built.