Incheon, port city, Gyeonggi do (province), northwestern South Korea. It lies near the mouth of the Han River, 25 miles (40 km) west-southwest of Seoul, with which it is connected by highway and railroad. It serves as the capital's chief seaport and is the site of South Korea's main international airport.

Seoul, city and capital of South Korea (the Republic of Korea). It is located on the Han River (Han-gang) in the northwestern part of the country, with the city center some 37 miles (60 km) inland from the Yellow Sea (west). Seoul is the cultural, economic, and political center of South Korea.