Like tiny gems of a necklace, the Northwest Hawaiian Islands stretch across the vast Pacific. Popularly called the Leewards, most were discovered in the 19th century. The Leewards are the oldest islands of the Hawaiian chain, believed to have emerged from the sea 25-30 million years ago. Slowly they floated west-northwest past the suboceanic hot spot as the other islands were built.
Measured from Nihoa Island, about 100 miles off the northwestern tip of Kaua‘i, they span just under 1,100 miles to Kure Atoll. There are islets, shoals, and half-submerged reefs in this chain: Kure, Midway, Pearl, and Hermes Atolls and Lisianski, Maro Reef, Gardner Pinnacles, French Frigate Shoals, Necker, and Nihoa. Most have been eroded flat by the sea and wind, but a few tough volcanic cores endure. Together they make up a landmass of approximately 3,500 acres, the largest being the three Midway islands, taken together at 1,580 acres, and the smallest is Gardner Pinnacles at six acres.
Politically, the Leewards are administered by the City and County of Honolulu, except for Midway, which is under federal jurisdiction. None, except Midway, are permanently inhabited, but there are some lonely wildlife field stations on Kure and the French Frigate Shoals. All, except for Midway Atoll, are part of the Hawaiian Islands National Wildlife Refuge, established at the turn of the 20th century by Theodore Roosevelt.
In 1996, following the closure of the Naval Air Base on Midway Island, Midway Atoll was turned over to the Department of the Interior and is now administered as the Midway Atoll National Wildlife Refuge. In June 2006, this 140,000-square-mile string of 10 islands and atolls and their surrounding waters, roughly 1,400 miles long and 100 mile wide, were officially designated a Marine National Monument, effectively creating the nation’s largest wilderness preserve and the world’s largest marine preserve.