In the northwestern portion of Lake Superior is a unique and remote island archipelago. Isle Royale National Park preserves 132,018 acres of land that was federally designated as wilderness on October 20, 1976. The park consists of one large island surrounded by over 450 smaller islands; it encompasses a total area of 850 square miles including submerged land, which extends 4 1/2 miles out into the largest fresh water lake in the world. Isle Royale's unique ecosystem led to it being designated an International Biosphere Reserve in 1980.