The seonso in naval post within the jurisdiction of JeollaJwasuyeong were mostly established when or before each navel post was set up. That is, they were mostly established between the reign of King Taejo and King Jungjong. The installation and origin of Eup Seonso were deeply connected to the changing military defense system of Joseon during the former half of its history. The Jingwan system, which had been the basis of national defense system since 1457년(third year of King Sejo's rule), was replaced with the new system of Jeseungbangryak around Eulmyowaebyeon(tenth year of King Myeongjong's rule), which brought considerable changes to the maritime defense system. The naval forces grouped together only the naval posts along the coast and organized them into Jingwan under the old Jingwan system, connecting them to no administrative districts. Under the system of Jeseungbangyrak, however, they built the naval forces in the Eups along the coast and even near Jujin as well as the naval posts and put them under the jurisdiction of naval forces Jeoldosa. As a result, Eupsugun was created in each Eup, and Seonso were established at places where the Eupsugun could be stationed and warships could be built and moored.
Most of naval post Seonso were located right in front of the south gates of naval posts with two exceptions: Bangdapjin and Yeodojin Seonso lied outside the south and north gates, respectively, thus holding a unique position. Eup Seonsos were scattered around the region with Suncheonbu Seonso in Shingi-dong of current Yeosu City, Jangheungbu Seonso in Haechang-ri, Anryang-myeon of current Jangheung-kun, Boseonggun Seonso in Seonso Village, Obong-ri, Deukryang-myeon of current Boseong-kun, Nakamgun Seonso in Jinseok Village, Jangyang-ri, Beolgyo-eup of current Boseong-kun, Heungyanghyeon Seonso in Deokheung-ri, Dohwa-myeon of current Goheung-kun, and Gwangjanghyeon Seonso in Jinwol-ri, Jinwol-myeon of current Gwangyang-kun.
Each Seonso was located in a point of strategic importance not exposed to the distant sea or outside.
As for the operation of Seonseo, the supreme commander of naval post was in charge of naval post Seonso with his subordinates including Uhu, Gyosu, and Gamjojeonseonchulnapgungwan taking the field responsibilities. Under their supervision, a good number of people were active at the Seonsos. Eup Seonsos were taken care of by the captain that was followed by Bangseonjang, Gipaegwan, Podogwan, Hundo, Gungigamgwan, Seonchanggamgwan, Sabu, Hwapojang, Posu, Tagong, Sagong, Musang, Yosu, Jeongsu, and Neungrogun.
Not all of them were regular employees since only the essential members including Bangseonjang, Gipaegwan, Podogwan, and Hundo as well as the captain were regular employees.
Eup Seonso where those members were active were under the jurisdiction of concerned Eups, which means that their operation was in principle the right and duty of Eup heads. Each Eup took care of a lot of work and covered all the aspects of operation with the exception of military affairs, which were under the authority of Jeolla Jwasusa of Jeolla Jwasuyeong rather than the Eup heads.
There were many public facilities including Seonchang, Jujeupgo, and Sugungi at each of those naval post Seonsos and Eup Seonso that were operated in those ways.