About three thousand islands, mostly small and uninhabited, lie off the western and southern coasts of South Korea. Jeju-do is about  off the southern coast of South Korea. It is the country's largest island, with an area of . Jeju is also the site of South Korea's highest point: Hallasan, an extinct volcano, reaches  above sea level. The easternmost islands of South Korea include Ulleungdo and Liancourt Rocks (Dokdo/Takeshima), while Marado and Socotra Rock are the southernmost islands of South Korea.