Gunsan, also romanized as Kunsan, is a city in Jeonbuk State, South Korea. It is on the south bank of the Geum River just upstream from its exit into the Yellow Sea. It has emerged as a high-tech manufacturing industrial city and an international trade seaport that is approximately 200 km southwest of Seoul on the midwest coast of the Korean Peninsula. Kunsan Air Base operated by the United States Air Force is in the city. To encourage investment, a free trade zone has been declared.