This Jeju is for the province of Jeju-do. For the city Jeju, go to Jejuball
Jeju-doball also known as Cheju-doball and officially called as the Jeju Special Autonomous Provinceball, is an island provinceball of South Koreaball. There are two Jejuballs. This Jejuball is the province Jejuball, not the city Jejuball.
Jeju-doball has the tallest mountain in South Korea, known as the Halla Mountain at 1,950m.
During the Korean War, the mainland was a battlefield, but Jeju-doball was peaceful. Not even a bullet was shot to Jeju-doball.
Today, it is one of the famous travel places of South Koreaball
No, North Korea can't nuke it.