Jeju is both an island and a province in South Korea, even though it is more commonly known as Jeju Island or Jejudo.
("Do" means either "island" or "province" depending on the context.)
Jeju is the biggest Korean island and is considered the number one honeymoon destination within South Korea.
It is the home of many tourist attractions such as Mt. Halla, Sangumburi Crater, and Olle Trail.
Jeju dialect (or accent) is very "thick" and most Koreans have a hard time understanding words spoken in traditional Jeju style.
In 2010, UNESCO has included Jeju language in the Atlas of languages in danger since the younger generations of Jeju are speaking less and less of the dialect.