Johnston Atoll National Wildlife Refuge

 Johnston Atoll National Wildlife Refuge is comprised of four islands (Johnston, Sand, North and East Island), and is located 716 nautical miles southwest of Honolulu. The formation of the atoll began 70 million years ago through a series of underwater volcanic eruptions. Johnston and Sand Island were designated as federal bird refuges in 1926 and retained its status as a refuge after the U.S. Navy took control of it in 1934. By 1964 dredge and fill operations had increased the size of Johnston Island from 46 acres to 596 acres. Sand Island was increased from 10 acres to 22 acres, and the addition of 25 acres of North Island and 18 acres of East Island were added to the atoll. Johnston Island played an important role in the United States’ nuclear testing program, which began in the late 1940s. From the late 1950s to 1962, high-altitude nuclear testing was carried out at Johnston Atoll. Chemical munitions were also stockpiled on Johnston and subsequently incinerated in the Johnston Atoll Chemical Agent Disposal System, that was built in 1990 and disassembled in 2004 after the completion of its mission. By November 2003, the U.S. Air Force completed clean-up and demolition of the incinerator buildings. By May 2005, almost all of Johnston Island's infrastructure had been removed, and all personnel left the atoll, including refuge staff. On January 6, 2009, the Pacific Islands Heritage Marine National Monument was established, which included Johnston Atoll National Wildlife Refuge within its boundaries. By secretary’s order, the boundaries of the Monument were established at 50 nautical miles out from the islands shoreline. On September 25, 2014, the monument was expanded around Johnston Atoll out to 200 nautical miles. The U.S. Air Force retains administrative jurisdiction over emergent lands at Johnston Atoll; however, the atoll is managed as a national wildlife refuge.