Jeju-do (Korean for "Jeju Province") is the a province in South Korea. Most of Jeju Province is Jeju Island, which is the largest island in South Korea. The island was created as a result of a volcanic eruption. Jeju-do is in the southern part of South Korea. Many people visit this island on honeymoon or to sight-see. Because Jeju-do is in the southern part of South Korea, it's warmer than the rest of South Korea.