Olkhon (Ольхон, also transliterated as Olchon) is the third-largest lake-bound island in the world. It is by far the largest island in Lake Baikal in eastern Siberia, with an area of 730 square kilometres . Structurally, it acts as the southwestern margin of Academician Ridge. The island measures 71.5 kilometres in length and 20.8 kilometres in width.