U.S. Minor Outlying Islands

Scattered across millions of square kilometers of Pacific Ocean—with one outlier in the Caribbean—the United States Minor Outlying Islands represent some of the most remote and inaccessible territories on Earth. These nine island groups are not a country in any conventional sense. They share no common culture, no indigenous population, no government, and no economy. What they share is sovereignty: each belongs to the United States, and together they form one of the most extraordinary collections of wildlife refuges, military outposts, and historical sites anywhere on the planet.

The designation itself is a bureaucratic creation. In 1986, the International Organization for Standardization grouped these territories together under ISO code "UM" for statistical convenience—which is why they appear on virtually every country dropdown menu on the internet, despite having no permanent residents and no postal service. Yet behind this statistical abstraction lie islands of staggering natural beauty and profound historical significance.

Midway Atoll witnessed one of the most decisive naval battles in history, turning the tide of the Pacific War in June 1942. Wake Island endured a heroic defense against Japanese invasion that same year. Howland Island was the intended destination of Amelia Earhart when she vanished over the Pacific in 1937. Johnston Atoll served as a nuclear test site and chemical weapons destruction facility during the Cold War. And Palmyra Atoll harbors one of the last pristine coral reef ecosystems left on Earth, a living laboratory for marine scientists studying what tropical oceans looked like before human impact.

For travelers, these islands present an honest paradox: they are among the most fascinating places in the American domain, yet almost entirely closed to the public. Most are protected as National Wildlife Refuges, accessible only with special permits. Wake Island hosts a U.S. Air Force installation. Understanding these remote outposts means understanding something essential about American reach, military history, and the raw power of the Pacific Ocean itself.

The name "United States Minor Outlying Islands" is purely an administrative invention. No one who lives or works on any of these islands would describe their location using this term. Created by the International Organization for Standardization in 1986, it groups nine geographically scattered territories under a single code (ISO 3166-1 alpha-2: UM) for statistical purposes. Before 1986, five of the Pacific islands were grouped as "United States Miscellaneous Pacific Islands" under a separate code.

The islands are neither administered collectively nor share a cultural or political history beyond being uninhabited territory under U.S. sovereignty. Each island has its own distinct story—some claimed under the Guano Islands Act of 1856, others acquired through military conquest or diplomatic agreement. The internet country code ".um" was assigned but retired in January 2007, since no one actually lived there to use it.

Legally, all except Palmyra Atoll are unincorporated, unorganized territories of the United States. Palmyra holds the unique distinction of being the only incorporated territory—a legal technicality resulting from its separation from the Territory of Hawaii when Hawaii became a state in 1959. This means the U.S. Constitution applies in full to Palmyra Atoll, making this uninhabited coral atoll one of the most legally protected patches of American soil.

The U.S. flag flies over all nine territories, though each island has unofficial flags and emblems used by the military bases and wildlife refuge stations that operate there.

The nine island groups span an enormous swath of the globe. Eight lie in the Pacific Ocean—scattered across Polynesia, Micronesia, and the Hawaiian archipelago—while one sits in the Caribbean Sea between Haiti and Jamaica. Combined, their total land area is a mere 34.2 square kilometers, but the exclusive economic zones surrounding them encompass hundreds of thousands of square kilometers of ocean.

The Pacific Islands

The Caribbean Island

These islands are all outside the customs territory of the United States. The Pacific islands are surrounded by large exclusive economic zones and most lie within the boundaries of the Pacific Remote Islands Marine National Monument, one of the world's largest protected marine areas.

The history of these islands is intertwined with American expansion across the Pacific, the brutal theater of World War II, and the shadowy operations of the Cold War. Most came under U.S. control through the Guano Islands Act of 1856, which allowed American citizens to claim any uninhabited island containing guano deposits. In the mid-19th century, guano—accumulated bird droppings rich in nitrogen and phosphorus—was enormously valuable as agricultural fertilizer, and dozens of Pacific islands were claimed under this law.

The Battle of Wake Island (December 1941) became one of the earliest American engagements of World War II. A small garrison of U.S. Marines and civilian contractors defended Wake against Japanese invasion for 16 days, initially repelling the first amphibious assault—a rare early success that boosted American morale. The island fell on December 23, 1941, and its defenders endured over three years of brutal captivity.

The Battle of Midway (June 4–7, 1942) was the turning point of the Pacific War. American codebreakers had deciphered Japanese plans to attack Midway Atoll, allowing Admiral Chester Nimitz to position his outnumbered fleet for an ambush. In a matter of minutes, American dive bombers destroyed three Japanese aircraft carriers, followed by a fourth later that day. Japan lost four fleet carriers, a cruiser, and hundreds of experienced pilots—losses from which the Imperial Japanese Navy never recovered.

During the Cold War, Johnston Atoll served as a nuclear testing site, witnessing atmospheric detonations including the spectacular Starfish Prime test of 1962—a 1.4-megaton hydrogen bomb detonated at 400 kilometers altitude that created an artificial aurora visible from Hawaii. Later, Johnston became the primary site for destroying the U.S. chemical weapons stockpile, a process completed in 2000. The military departed in 2004.

In 1935, a colonization program attempted to settle young Hawaiian men on Baker, Howland, and Jarvis islands to strengthen American sovereignty claims. These colonists were evacuated in 1942 when Japanese forces attacked, killing two young men on Howland Island. On July 2, 1937, Howland Island was the intended destination of Amelia Earhart during her attempted around-the-world flight. She never arrived, and her disappearance remains one of aviation's greatest mysteries.

Midway Atoll lies almost exactly halfway between North America and Asia—hence its name—at the northwestern end of the Hawaiian archipelago, some 2,000 kilometers from Honolulu. Though geographically part of the Hawaiian chain, Midway was never incorporated into the state. Its three small islands—Sand, Eastern, and Spit—enclose a lagoon of stunning turquoise waters, surrounded by one of the most biologically rich coral reef systems in the Pacific.

Today, Midway is part of the Papahānaumokuākea Marine National Monument, a UNESCO World Heritage Site encompassing 1.5 million square kilometers of protected ocean. The atoll serves as the world's largest nesting ground for the Laysan albatross, with over a million pairs breeding each season. The enormous birds—nicknamed "gooney birds" by the military personnel who once shared the island—blanket every available surface during nesting season.

Remnants of the military era stand as haunting monuments. The rusting hangars, concrete bunkers, and overgrown streets of what was once a bustling Naval Air Station now belong entirely to the birds. A small U.S. Fish and Wildlife Service team of approximately 40 staff manages the refuge, rotating in and out every few months. Tourist access has been suspended since 2012 due to budget constraints.

One of Midway's most heartbreaking contemporary stories is the impact of ocean plastic. Albatross parents, foraging across thousands of kilometers of Pacific, mistake floating plastic debris for food and feed it to their chicks. Photographer Chris Jordan's images of dead albatross chicks, their stomachs filled with bottle caps and cigarette lighters, became iconic symbols of the ocean plastic crisis.

Wake Island—technically an atoll comprising three islands (Wake, Wilkes, and Peale)—sits in the North Pacific approximately 3,700 kilometers west of Honolulu and 2,400 kilometers east of Guam. At 6.5 square kilometers, it is the largest of the Minor Outlying Islands and the only one with a significant permanent military presence. The U.S. Air Force operates Wake Island Airfield, maintaining a strategic refueling and emergency landing point for transpacific military and commercial aircraft.

The island's place in history was sealed during the Battle of Wake Island in December 1941. A garrison of 449 Marines, 68 Navy personnel, and approximately 1,200 civilian construction workers faced an overwhelming Japanese invasion force. In an extraordinary act of defiance, the defenders initially repelled the first assault on December 11—sinking two Japanese destroyers and damaging several other warships. When a much larger force returned on December 23, Wake finally fell.

Today, approximately 100 military and contractor personnel maintain the base. The island retains its strategic importance as a mid-Pacific logistics and emergency diversion point. During the late 2010s, the U.S. military began reinvesting in Wake's infrastructure amid growing strategic competition in the Pacific. Access is strictly limited to authorized personnel—there is no tourism.

The Marshall Islands' government has a longstanding sovereignty claim over Wake, which the Marshallese call "Ānen Kio" (island of the kio flower). This claim has never been formally resolved, though the United States exercises undisputed de facto control.

Palmyra Atoll is perhaps the most remarkable of all the Minor Outlying Islands—a lush, rain-drenched tropical paradise roughly 1,600 kilometers south of Honolulu that harbors one of the most pristine coral reef ecosystems remaining on Earth. Unlike the barren, sun-scorched atolls elsewhere in this collection, Palmyra receives abundant rainfall (over 4,400 mm annually) and supports dense tropical vegetation including towering coconut palms and Pisonia forests.

Legally, Palmyra holds a unique position. When Hawaii became a state in 1959, Palmyra—which had been part of the Territory of Hawaii—was explicitly excluded from statehood, making it the only remaining incorporated territory of the United States. The full protections of the U.S. Constitution apply on Palmyra, a distinction shared with no other outlying territory.

The atoll is jointly managed by the U.S. Fish and Wildlife Service and The Nature Conservancy, which purchased it in 2000. A small research station supports rotating teams of marine biologists studying coral reef health, shark populations, and tropical ecology in a system largely free from human disturbance. Palmyra's reefs teem with apex predators—the biomass of sharks and other large fish here is estimated to be among the highest anywhere on Earth.

Palmyra is also notable for its dark history. In 1974, a double murder on the atoll became one of the most sensational criminal cases in American history, later recounted in Vincent Bugliosi's book And the Sea Will Tell. During World War II, the U.S. Navy built an airfield and stationed up to 6,000 troops on this tiny atoll—though nature has since reclaimed much of the military infrastructure.

Baker Island and Howland Island are tiny, low-lying coral islands straddling the equator in the central Pacific, roughly 3,000 kilometers southwest of Honolulu. Both were claimed by the United States and Great Britain in the 19th century for their guano deposits, and both were extensively mined before being abandoned.

In 1935, the U.S. government launched the American Equatorial Islands Colonization Project, recruiting young Hawaiian men—mostly students from the Kamehameha Schools—to live on Baker, Howland, and Jarvis islands as homesteaders. The program ended tragically when Japanese aircraft attacked Howland Island on December 8, 1941, killing two colonists—among the earliest American civilian casualties of World War II.

Howland Island's most famous connection is to Amelia Earhart. On July 2, 1937, a day-use landing strip had been constructed on Howland specifically for Earhart's around-the-world flight. The U.S. Coast Guard cutter Itasca waited offshore to guide her in by radio. Earhart's final transmissions indicated she was near Howland but could not locate the tiny island. She was never seen again. Today, the Earhart Light—a day beacon erected in her memory in 1938—still stands on Howland's western shore.

Both islands are now National Wildlife Refuges, closed to the public. They support important seabird colonies and green sea turtle nesting populations.

Jarvis Island, also known as Bunker Island, lies in the South Pacific roughly halfway between Hawaii and the Cook Islands. At 4.5 square kilometers, it is the largest of the equatorial Line Islands in this collection but remains entirely uninhabited, undeveloped, and largely devoid of vegetation. The island rises barely 7 meters above sea level at its highest point—a flat, sun-blasted expanse of coral rubble and sparse grasses.

Like Baker and Howland, Jarvis was extensively mined for guano in the 19th century and was part of the 1935 colonization program. The young Hawaiian colonists who lived there described an existence of extreme monotony punctuated by the excitement of supply ships every few months. They were evacuated in 1942.

Today, Jarvis Island is a National Wildlife Refuge. Visitors require a special permit, rarely granted. The island's surrounding waters are among the richest in the central Pacific, supporting extensive coral reefs and large populations of reef fish, sea turtles, and nesting seabirds.

Johnston Atoll lies 1,300 kilometers southwest of Honolulu and has one of the most complex and troubling histories of any American territory. Originally a natural atoll of two small islands, Johnston was dramatically expanded during the Cold War by dredging operations that quadrupled its land area and created two entirely artificial islands.

During the late 1950s and early 1960s, Johnston served as a launch site for atmospheric nuclear tests. The most famous was Operation Fishbowl's Starfish Prime in July 1962—a 1.4-megaton thermonuclear warhead detonated at 400 kilometers altitude. The resulting electromagnetic pulse damaged electrical equipment in Hawaii, knocked out street lights in Honolulu, and created an artificial aurora visible across the Pacific. Several earlier tests had failed, contaminating the atoll with plutonium—contamination that persists to this day.

From 1971 to 2000, Johnston Atoll housed the Johnston Atoll Chemical Agent Disposal System (JACADS), the first facility to destroy the U.S. military's stockpile of chemical weapons, including nerve agents and mustard gas. The operation successfully destroyed over 6,000 tons of chemical munitions.

The military departed in 2004, and the atoll was transferred to the U.S. Fish and Wildlife Service. It remains heavily contaminated and closed to the public. Despite its toxic legacy, Johnston's surrounding waters support thriving coral reefs and marine life.

Kingman Reef barely qualifies as land. This triangular reef system, located about 60 kilometers north of Palmyra Atoll, is mostly submerged—only a few sandy spits rise above the waterline at low tide. Its total dry land area is estimated at just 0.01 square kilometers, making it the smallest territory in this collection.

What Kingman lacks in land, it compensates in marine biodiversity. Scientific surveys have found that Kingman's reefs are dominated by predators—sharks, groupers, and other apex species make up the majority of fish biomass, a distribution considered characteristic of truly pristine marine environments. This "inverted biomass pyramid" is so unusual that it has challenged conventional understanding of how reef ecosystems function.

Kingman Reef was briefly used as a seaplane base by Pan American Airways in the late 1930s, serving as a refueling stop on the Hawaii-to-American Samoa flying boat route. It is now a National Wildlife Refuge, closed to all public access.

Navassa Island is the odd one out—the only territory in this collection located not in the Pacific but in the Caribbean Sea, roughly 55 kilometers west of Haiti's Tiburon Peninsula. This small, uninhabited, elevated limestone island (5.4 square kilometers) rises sharply from the sea with cliffs reaching 75 meters, its plateau covered in dense scrub and cactus.

The United States claimed Navassa in 1857 under the Guano Islands Act. The guano mining operations that followed were marked by brutal labor conditions—the workers, primarily African Americans from Baltimore, endured such harsh treatment that they revolted in 1889, killing several supervisors. The subsequent murder trial, Jones v. United States, reached the Supreme Court and established important legal precedents regarding U.S. sovereignty over claimed islands.

Haiti has maintained a competing sovereignty claim over Navassa since its independence, citing the island's location on the Haitian continental shelf. The dispute remains unresolved, though the United States exercises de facto control. Navassa is currently a National Wildlife Refuge, home to the endangered Navassa rhinoceros iguana—found nowhere else on Earth.

The true wealth of the U.S. Minor Outlying Islands lies not in their land but in their ecosystems. Isolated by vast stretches of open ocean, these islands and their surrounding waters support biological communities of global significance.

The ocean plastic crisis represents the greatest modern threat to these remote ecosystems. Despite their extreme isolation, all of the islands accumulate marine debris carried by Pacific currents. Midway Atoll's albatross chicks have become tragic symbols of this global problem.

Climate varies significantly across the islands due to their vast geographic spread. The equatorial islands (Baker, Howland, Jarvis) experience hot, humid tropical conditions year-round with temperatures averaging 27–30°C. Palmyra receives extremely heavy rainfall—over 4,400 mm annually—making it the wettest of the group.

Midway Atoll, at 28°N latitude, experiences distinct seasons with cooler winters (15–20°C) and warm summers (24–28°C). Wake Island, at 19°N, enjoys a tropical marine climate with temperatures ranging from 24–32°C and a typhoon season from June through December.

Navassa Island in the Caribbean has a tropical climate around 26–30°C year-round, influenced by Caribbean hurricane patterns.

All of the low-lying atolls face existential threats from sea level rise. A 1-meter rise in sea levels would inundate most of Baker, Howland, Jarvis, and Kingman Reef entirely, destroying critical wildlife habitat and erasing historical sites.

Access & Permits

Nearly all islands are closed to the general public. Researchers may apply for special use permits through the U.S. Fish and Wildlife Service. Wake Island requires military authorization. Palmyra Atoll is the only island where civilian access is theoretically possible.

Health & Safety

There are no medical facilities on any of these islands except Wake Island's basic military clinic. Emergency evacuation could take days. There is no commercial transportation, no hotels, no restaurants, and no emergency services.

Communications

No civilian telephone or internet service. Military installations on Wake have satellite communications. Research stations on Midway and Palmyra have limited satellite connectivity. No postal service except military APO on Wake.

In practical terms, you almost certainly cannot visit these islands. But understanding how authorized personnel reach them illustrates their extreme remoteness.

Midway Atoll: Chartered aircraft from Honolulu (~2,000 km). USFWS rotates staff every few months.

Wake Island: Occasional military transport from Honolulu or Guam. 3,000-meter runway for large military aircraft.

Palmyra Atoll: Private vessel or charter aircraft from Honolulu (~1,600 km).

All other islands: Accessible only by vessel, typically departing from Honolulu. Journey times range from several days to over a week.

• "Shattered Sword: The Untold Story of the Battle of Midway"
  by Jonathan Parshall & Anthony Tully — The definitive account of the Battle of Midway from the Japanese perspective
• "Given Up for Dead: America's Heroic Stand at Wake Island"
  by Bill Sloan — The gripping story of Wake Island's defense and its defenders' captivity
• "And the Sea Will Tell"
  by Vincent Bugliosi — True crime classic about the 1974 double murder on Palmyra Atoll
• "Eye of the Albatross: Visions of Hope and Survival"
  by Carl Safina — Following Laysan albatrosses across the Pacific, centered on Midway Atoll
• "The Last Stand of the Tin Can Sailors"
  by James D. Hornfischer — Pacific naval warfare epic providing context for these island battles

Have photos from these remote islands? Send to photos@kaufmann.wtf to be featured.

Remote Pacific Atoll

Aerial view of a pristine Pacific atoll