Extending northwest from the Hawaiian islands of Ni'ihau and Kaua'i ist the Hawaiian Archipelago or the Leeward Islands that extends for nearly 1.523 miles or about 2.437 kilometers. This Archipelago is made up of 26 islets, reefs and shoals which mark the summits of submarine volcanoes. The islands west of Gardner Pinnacles (one of the 26 islets) are mostly low coral reefs and shoals, while the islets east of Gardner Pinnacles are mostly the remainds of basaltic cones. Coralline algae and corals are the principal components of the living and emerged reefs.
The group of the forebidden Hawaiian Islands consists of Kaula, Nihoa, Necker, The French Frigate Shoals and the La Pérous Pinnacle, Gardner Pinnacle with Maro Reef, Laysan Reef, Lisiansky Island, The Perl & Hermes Reefs, Midway and Kure Reef, the most outernmost of the group. All islands are absolutely closed for public and are adminstered by the Hawaii Fish and Wildlife Office.