Yeosu, city, South Jeolla do (province), on Yeosu Peninsula, extreme southern South Korea. Such large islands as Namhae, Dolsan, and Geumo protect its natural port. The Korean navy headquarters were located there during the Joseon (Yi) dynasty (1392–1910) before being moved to Tongyeong. With neighboring Suncheon, the city was part of the Yeosu-Suncheon Rebellion in 1948. In 1949 Yeosu became an open port with the status of a municipality.
Yeosu is connected to Seoul by rail through Gwangju and Daejeon, and it has regular sea lines to Busan, Mokpo, and Jeju. The harbor is divided into two parts: the old western port is used mainly for fishing, and the newer eastern port for trade. The city exports fresh fish. Petrochemical, oil-refining, and other industries have been developed in the Yeosu Industrial Complex. The city’s harbor and shoreline were the site of Expo 2012, an ecologically conscious world’s fair whose theme was the importance of the world’s oceans and coastlines. Pop. (2020) 271,505.