Jeju Island is considered a first-tier city in South Korea

Third-tier cities. Jeju Island is a small city in South Korea and is considered a third-tier city in South Korea. Jeju Island is the largest island in South Korea. It is located in the southwestern waters of South Korea, with an area of ??1,845 square kilometers and a population of 668,000. The island has a pleasant climate and is a famous tourist island. There is Jeju City on the north coast.