Johnston Atoll

Johnston Atoll is an unincorporated territory of the United States, managed by the United States Air Force. Because it is closed to the public, only people with special permission can visit. To get there by boat or swim in the nearby waters, people also need permission from the United States Fish and Wildlife Service. These waters are part of a National Wildlife Refuge and the Pacific Islands Heritage Marine National Monument.

Since 1934, the U.S. military has used this remote atoll for many purposes. It served as a place for ships to refuel, an airbase, and even a testing site for nuclear and biological materials. Sadly, these activities caused pollution, but cleanup efforts finished in 2004. Today, the Air Force only checks on the environment sometimes.

Even though the island has a tough history, it is now an important home for many seabirds and sea creatures. Teams work hard to keep the wildlife safe. In the past, a harmful bug called the yellow crazy ant was hurting the birds, but it was removed by the 2020s.

Originally, Johnston Atoll had two islands, Johnston and Sand Island, surrounded by a coral reef. Over time, people made the islands bigger and created two new ones, North and East, mostly by moving coral. A long runway was built on Johnston, and channels were made through the reef to help ships and planes.

Geography

Johnston Atoll is a small island group in the North Pacific Ocean, about 750 nautical miles southwest of Hawaiʻi. It is part of the United States Minor Outlying Islands. The atoll has four islands: Johnston Island, Sand Island, and two smaller islands called Akau (North) and Hikina (East). Some of the islands were made bigger by moving sand and coral from the ocean floor.

The islands cover about 2.67 square kilometers. There is a shallow area of water, called a lagoon, around part of the islands.

Climate

The climate on Johnston Atoll is tropical but usually dry. The northeast trade winds blow steadily, and temperatures do not change much through the year. The islands rise from sea level to about 5 meters (16 feet) at Summit Peak. They have low plants and palm trees on flat land but no natural sources of fresh water.

Johnston Atoll has a hot semi-arid climate (Köppen: BSh; Trewartha: BSha). It is a dry island with just over 26 inches (660 mm) of rain each year.

Wildlife

The waters around Johnston Atoll are home to about 300 different kinds of fish. The area is also a place where green turtles and Hawaiian monk seals visit. There is a chance that humpback whales might use these waters for breeding, though only in small numbers and not regularly. Many other whales and dolphins may also pass through the area.

Birds

The atoll is an important place for many seabirds. Birds that live and breed there include Bulwer's petrel, wedge-tailed shearwater, Christmas shearwater, white-tailed tropicbird, red-tailed tropicbird, brown booby, red-footed booby, masked booby, great frigatebird, spectacled tern, sooty tern, brown noddy, black noddy, and white tern. This is the largest home for red-tailed tropicbirds in the world, with 10,800 nests counted in 2020. The island is also visited by migratory shorebirds such as the Pacific golden plover, wandering tattler, bristle-thighed curlew, ruddy turnstone, and sanderling. Because of its important bird homes, the island and its waters are recognized as an Important Bird Area by BirdLife International.

Flora

The first list of plants found on Johnston Atoll was published in 1931. It included three types of plants: Lepturus repens, Boerhavia diffusa, and Tribulus cistoides. Later, during the 1940s when the island was used for aviation, another plant called Pluchea odorata was brought from Honolulu.

• Lepturus repens
• _(4938290660).jpg)
• Boerhavia diffusa
• Tribulus cistoides

History

Early history

The first Western record of the atoll was on September 2, 1796, when the American ship Sally accidentally ran aground near the islands. The captain, Joseph Pierpont, shared his experience in newspapers the next year. The islands were not named until December 14, 1807, when they were seen from HMS Cornwallis of the Royal Navy, commanded by Captain Charles James Johnston.

In 1856, the United States passed a law allowing citizens to claim islands with bird droppings. William Parker and R. F. Ryan found the atoll and claimed it for the United States in 1858. Later that year, another group claimed it for the Kingdom of Hawaii, but the United States held onto its claim.

National Wildlife Refuge since 1926

In 1926, President Calvin Coolidge made the atoll a federal bird refuge. It became part of the United States National Wildlife Refuge system in 1926 and was renamed the Johnston Island National Wildlife Refuge in 1940. The atoll was established to protect its tropical ecosystem and wildlife.

In 1990, two full-time U.S. Fish and Wildlife Service personnel were stationed on Johnston Atoll. After the military mission ended in 2004, the atoll was administered by the Pacific Remote Islands National Wildlife Refuge Complex. In 2009, it became part of the Pacific Remote Islands Marine National Monument, which includes over 800,000 acres of water.

Military control 1934–2004

In 1934, President Franklin D. Roosevelt transferred control of Johnston Atoll to the United States Navy. The U.S. Air Force took control in 1948. The atoll was used for high-altitude nuclear testing between the late 1940s and 1962. Operational control moved to the Defense Special Weapons Agency in 1973, then back to the Air Force until the base closed in 2004.

Sand Island seaplane base

In 1935, the U.S. Navy began minor construction for seaplane operations. They enlarged the island, built buildings, and created a seaplane landing area. Several seaplanes flew between Hawaii and Johnston Atoll. After World War II, a seaplane base was further expanded with a causeway, barracks, and other facilities.

Airfield

Construction of an airfield began in 1941. It was used as a refueling stop for submarines and bombers during World War II. After the war, it was used commercially until missile launches caused flights to stop. The runway remained until it was decommissioned in 2003.

World War II 1941–1945

On December 7, 1941, the day Japan attacked Pearl Harbor, USS Indianapolis was unloading supplies at Johnston Atoll. The atoll was shelled by a Japanese submarine on December 15, 1941, and again on December 22 and 23, 1941. Johnston Atoll's coastal artillery defended against these attacks.

Coast Guard mission 1957–1992

In 1957, the U.S. Coast Guard began operating a navigation station on Johnston Atoll. The station helped improve navigation accuracy in the Central Pacific. The station ceased operations in 1992, and its equipment was removed.

National nuclear weapon test site 1958–1963

Between 1958 and 1975, Johnston Atoll was used for American nuclear tests. In 1958, two nuclear tests were conducted as part of Operation Hardtack I. The atoll was also used to launch sounding rockets for scientific purposes.

Eight missiles were launched from Johnston Island in 1962 as part of Operation Fishbowl. The "Starfish Prime" test in 1962 created bright auroras visible in Hawaii and disrupted some communication systems.

Anti-satellite mission 1962–1975

From 1962 to 1975, Johnston Atoll was used for an anti-satellite weapon program. Modified missiles were launched to test the capability to destroy satellites. The program was discontinued in 1975.

Baker–Nunn satellite tracking camera station

A satellite tracking camera station was built on Sand Island in 1965. It was used until 1975 when operations moved to other locations.

Johnston Island Recovery Operations Center

A recovery center was built in 1961 to retrieve film canisters from reconnaissance satellites. The center was responsible for collecting data from satellites and missiles.

Biological warfare test site 1965–1968

From 1965 to 1968, the atoll was used for biological warfare testing. Tests were conducted to assess the effects of biological agents on ships and other targets.

Chemical weapon storage 1971–2001

Starting in 1971, Johnston Atoll became a storage site for chemical weapons. Weapons were brought from Okinawa and stored in secure areas on the island.

Agent Orange storage 1972–1977

Agent Orange was stored on Johnston Atoll from 1972 to 1977. It was eventually destroyed in 1977 on a Dutch ship.

Chemical weapon demilitarization mission 1990–2000

The Johnston Atoll Chemical Agent Disposal System was built to destroy chemical weapons. Operations began in 1993 and were completed in 2000. The facility was demolished by 2003.

Closure and remaining structures

In 2003, structures and facilities were removed, and the runway was closed. The last official flight left on June 15, 2004. The only remaining structures are the Joint Operations Center building, chemical bunkers, and a Quonset hut.

Contamination and cleanup

Over the years, leaks of Agent Orange and chemical weapons occurred. Studies have been conducted to assess contamination. Cleanup efforts have included removing contaminated soil and building a sealed landfill for radioactive materials.

After closing

In 2005, the atoll was briefly offered for sale but the sale was withdrawn. In 2006, Hurricane Ioke struck the atoll, but all personnel safely sheltered in the JOC building. In 2007, the Coast Guard used the runway to rescue a fisherman. In 2010, efforts began to eradicate invasive ants, which were fully removed by 2021. In 2025, the Air Force plans to use the atoll for testing reusable rocket cargo delivery.

Demographics

Johnston Atoll has never had any native people living there. In the late 20th century, there were usually around 300 American military personnel and 1,000 civilian workers on the island at any time. Today, the island has no permanent residents except for a small group of workers with the Crazy Ant Strike Team project, who stay for six months with very little contact with the outside world.

The main ways to get to the island were by airplane using the airport’s paved military runway, or by ship through a pier and channel in the coral reef. The island had many ways to communicate, including telephone lines, a submarine cable, satellite links, and radio systems. Amateur radio operators sometimes sent messages from the island using the KH3 call-sign. In 1966, an underwater cable was laid between Hawaii and the island’s Air Force Base, and in 1993, a satellite station was added to improve communications.

Areas

Launch facilities