Busan, officially Busan Metropolitan City, is South Korea's second most populous city after Seoul, with a population of over 3.3 million as of 2024. Formerly romanized as Pusan, it is the economic, cultural and educational center of southeastern South Korea, with its port being South Korea's busiest and the sixth-busiest in the world. The surrounding "Southeastern Maritime Industrial Region" is South Korea's largest industrial area. The large volumes of port traffic and urban population in excess of 1 million makes Busan a Large-Port metropolis using the Southampton System of Port-City classification. As of 2025, Busan Port is the primary port in Korea and the world's sixth-largest container port.