Aleutian Islands
The Aleutian Islands cross longitude 180 degrees, the line where east and west longitude end. Because the chain straddles it, the United States holds both its westernmost and its easternmost points by longitude right here. Amatignak Island marks the western extreme, and Semisopochnoi Island marks the eastern one.
The native name for the chain is Unangam Tanangin, which means land of the Aleuts. It counts 14 larger volcanic islands and 55 smaller ones. Across them rise 57 volcanoes, which form the northernmost stretch of the Pacific Ring of Fire. Few places in the northern Pacific are more isolated.
What forces raised this arc out of the sea, and why does it still shake and steam? What can grow or live on islands so far from everywhere? Who reached them first, who claimed them, and who fought over them? And how do people make a living on land like this today?
Around 56 million years ago, volcanism and subduction jumped south to the line where the islands now stand. That jump trapped a slice of the old Kula Plate. It survives today as the ocean floor of the Aleutian Basin, north of the arc.
The island arc itself formed in the early Eocene, between 55 and 50 million years ago, when the Pacific Plate began to dive beneath the North American Plate. The arc is built from separate blocks that have rotated clockwise. Under the islands lie three layers of rock: Eocene volcanic rock, then marine sedimentary rock from the Oligocene and Miocene, then a Pliocene to Quaternary layer of sedimentary and igneous rock.
At Tanaga Island, near 178 degrees west, the chain swings from a southwest heading to a northwest one. That bend follows a curve in the line of volcanic fissures that built the islands. The Kuril Islands, the Japanese chain and the Philippines show similar curves. All of these arcs sit at the edge of the Pacific Plate and endure frequent seismic activity, yet people live on them.
Amber and beds of lignite turn up on the islands that are not wholly volcanic, along with crystalline and sedimentary rocks. The coasts are rocky and worn by surf. Mountains rise steeply from the water, which makes the approaches exceedingly dangerous for ships.
Makushin Volcano on Unalaska Island stands 5691 feet tall, and the tallest volcanic islands reach 6200 feet. From inside the town of Unalaska the cone itself is not quite visible. Its rising steam shows on a rare clear day. Residents who climb a smaller hill such as Pyramid Peak or Mt. Newhall get a clear view of the snow-covered cone.
Some of this land is very young. Bogoslof Island rose from the sea in 1796 and Fire Island in 1883, about 30 miles west of Unalaska Bay. In 1906 a new cone rose between the islets of Bogoslof and Grewingk, and another followed in 1907. An explosive eruption on the 1st of September 1907 nearly demolished both cones. In 2017 the volcanic cone erupted, sending ash and ice particles 30,000 feet into the air, about 9000 meters.
Counting from east to west, the first of six island groups is the Fox Islands, whose main islands are Unimak, Akutan, Unalaska and Umnak. Next come the Islands of Four Mountains, with Yunaska and Chuginadak. The Andreanof Islands follow, led by Adak, Atka, Amlia, Seguam, Kanaga and Tanaga. After them come the Rat Islands, with Kiska and Amchitka.
The Near Islands hold Attu, Agattu and the Semichi group of Alaid, Nizki and Shemya. The Commander Islands, with Bering and Medny, close the list.
All six groups lie between 51 and 55 degrees north latitude, and between 172 degrees east and 163 degrees west longitude. The islands cover a land area of 6,821 square miles, or 17,666 square kilometers. The chain stretches roughly 1200 miles west from the Alaska Peninsula mainland. It divides the Bering Sea to the north from the Pacific Ocean to the south.
Attu, Unalaska, Umnak and Unimak rank as the largest islands. Unimak is the biggest of these, at 1,571.41 square miles, or 4,069.9 square kilometers. Unalaska is the only other island above 1,000 square miles. The chain is a western continuation of the Aleutian Range on the mainland, and elevation is greatest in the eastern islands and least in the western ones.
The Commander Islands lie farthest west, and they belong to Russia rather than the United States. They form the Aleutsky District of Kamchatka Krai, in the Russian Far East. Bering Island and Medny Island are the chief members. Among the rocky outcrops are Sea Lion Rock, Sea Otter Rocks and Tufted Puffin Rock.
Three books written decades apart tie the Aleutians to Oceania because the islands are remote ones in the Pacific. They are Alfred Russel Wallace's 1879 Australasia, Ian Todd's 1974 Island Realm: A Pacific Panorama, and Dean Kohlhoff's 2002 Amchitka and the Bomb: Nuclear Testing in Alaska. Yet the islands share biogeographic and cultural ties with North America, so they are not ordinarily counted in that region.
In real terms, Attu is the westernmost American island, and the International Date Line runs just west of it.
Unalaska gets about 80 inches of rain a year, spread across roughly 250 rainy days. It is said to be one of the rainiest places in the United States. Fog is almost constant, and temperatures stay moderate and fairly uniform.
The mean annual temperature at Unalaska, the most populated island, is about 38 degrees Fahrenheit, or 3 degrees Celsius. January averages about 30 degrees Fahrenheit and August about 52. The recorded extremes across the islands are 78 degrees and 5 degrees Fahrenheit, or 26 and minus 15 Celsius.
Under the Köppen classification, one zone of the islands counts as subpolar oceanic, type Cfc. Reykjavik, Tórshavn, Punta Arenas, Ushuaia and the Auckland Islands share that type. Farther northeast the climate shifts to subarctic with cool summers and year-round rainfall, type Dfc, like Murmansk, St. Moritz and Labrador City. In winter the islands sit at the center of a semi-permanent low-pressure area called the Aleutian Low. Summers are much cooler than around Sitka in Southeast Alaska, while winter temperatures nearly match those of the Alaska Panhandle.
The growing season lasts about 135 days, from early May to late September. Apart from some stunted willows, the chain has almost no native trees. A few conifers on Adak and Amaknak are remnants of the Russian period. Some are estimated at two hundred years old, yet they rarely reach even 10 feet, and many stand under 5 feet. Winds as fierce as those on the Falkland Islands snap off taller trees. The so-called Adak National Forest is a man-made group of just 33 trees.
Instead of forest, the islands wear a dense carpet of crowberry, bluejoint, grasses, sedges and many flowering plants. Peat bog lies near the coasts. The endangered Aleutian shield fern is endemic to the islands.
Buldir Island supports 21 breeding seabird species, including the red-legged kittiwake, which is endemic to the Bering Sea. Large colonies also nest on Kiska, Gareloi, Semisopochnoi and Bogoslof. Vagrant birds from Asia turn up too, among them the common rosefinch, Siberian rubythroat, bluethroat and lanceolated warbler. The islands also produced the first North American record of the intermediate egret.
Cattle, caribou and foxes were introduced to the islands, and they compete with native wildlife, though the habitats remain largely unspoiled. Nearly all the land is protected within the Alaska Maritime National Wildlife Refuge and the Aleutian Islands Wilderness.
Along many coasts, sea otters act as a keystone species. They hold sea urchin numbers down, which lets kelp forests grow. Where urchins become too numerous, they clear away the kelp and leave behind urchin barrens.
Shredded stalks of beach rye were the material for baskets woven by the people of the Aleutians, who also developed skills in hunting and fishing. Many anthropologists hypothesize that the islands, stretching like a broken bridge between Asia and North America, served as a route for the first people of the Americas. The earliest known evidence of human occupation in the Americas lies much farther south. Early sites in the Bering Sea were probably submerged by rising waters and sand during the current interglacial period.
Two ships, the Saint Peter and the Saint Paul, set out on a Russian government voyage of discovery in 1741. Their commanders were Vitus Bering, who was Danish-born, and Aleksei Chirikov. A storm separated them. Chirikov found several eastern islands of the group, and Bering found several western ones.
Bering was shipwrecked and died in the Commander Islands. One island and the surrounding sea now carry his name. His surviving men built a boat from the wreckage and reached Kamchatka. They reported that the islands were rich in fur-bearing animals.
Siberian fur hunters flocked to the Commander Islands and gradually worked eastward across the Aleutians. That movement gave Russia a foothold on the northwestern coast of North America. By 1760 the merchant Andrian Tolstykh had made a detailed census near Adak and extended Russian citizenship to the Aleuts. In 1778, on his third and last voyage, Captain James Cook surveyed the eastern part of the archipelago. He fixed the positions of some important islands and corrected many errors of earlier navigators.
In the 1780s the merchant and seafarer Grigory Shelikhov founded a company built on the systematic exploitation of the native peoples. Conflict was sporadic. It often ended badly for the poorly armed, vastly outnumbered Russians, as in the Awa'uq Massacre.
The colonies nonetheless settled into a relatively stable arrangement based on cooperation and intermarriage. Official policy gave children of mixed Aleut-Russian birth social status, education and professional training. Within a generation, native-born Alaskans handled most of the day-to-day administration of the Russian-American colonies.
Breaking the usual colonial pattern, the Russians adopted local technology. They took up the Aleut kayak, called the baidarka, along with sea otter hunting techniques and the working of native copper deposits. They also set up public education and adapted the Cyrillic alphabet to write religious and other texts in Aleut. They vaccinated the native population against smallpox and enforced sea mammal conservation policies that were ahead of their time.
A party of ten Russian Orthodox monks and priests arrived in 1793. Within two years, a monk named Herman was the only survivor. He settled on Spruce Island, near Kodiak Island, and often defended the rights of the Aleuts against the Russian trading companies. The Orthodox Church now knows him as Saint Herman of Alaska.
Father Veniaminov reached Unalaska in 1824. He was named Bishop Innokentii in 1840 and moved to Sitka, and he is now known as Saint Innocent of Alaska. The principal settlements stood on Unalaska Island. The oldest, Iliuliuk, also called Unalaska, was settled between 1760 and 1775 and had a customs house and an Orthodox church.
In 1867, Russia transferred all its North American possessions to the United States in the Alaska Purchase. The chain, which had been called the Catherine Archipelago, passed into American hands.
On the 3rd of June 1942, Japanese forces landed on Attu and Kiska and occupied small parts of the islands. These were the only two invasions of the United States in North America during the war. The Philippines, Guam and Wake Atoll, Pacific territories of the United States, were also invaded. The landings possibly aimed to draw American forces away from the main Japanese attack at Midway Atoll.
The U.S. Navy had broken the Japanese naval codes, so it proceeded as if the landings were only a diversion. It did not spend large amounts of effort defending the islands. More than 90 Americans were taken to Japan as prisoners of war. The United States moved most of the remaining civilian population, over 800 people from the Aleutians and the Pribilof Islands, to camps in the Alaska Panhandle.
In May 1943, American forces invaded Japanese-held Attu and defeated the Japanese there. In August 1943, American and Canadian troops launched an invasion of Kiska. A force of 34,426 men took part. But the entire Japanese garrison of 5,183 men had slipped away on the 28th of July without the Americans noticing.
The empty invasion was an embarrassment for the Allies, and it still cost lives. A total of 313 men died through accidents, many of them from accidental fire. The campaign in the islands ended there.
President Roosevelt visited Adak in 1944, where he met commanders and ate with the soldiers of the garrison. It was his first and only trip to the Aleutians, and to Alaska as a whole. A rumor spread that he had accidentally left his Scottish Terrier, Fala, on one of the islands. The story said he sent a destroyer to retrieve the dog, at a cost to taxpayers of several million dollars.
Roosevelt joked about the rumor in a talk to the Teamsters Union in Washington DC, now known as the Fala Speech. He told the crowd, "Well, of course, I don't resent attacks, and my family doesn't resent attacks, but Fala does resent them!"
On the 3rd of June 2002, the governor of Alaska ordered state flags lowered to half-staff for Dutch Harbor Remembrance Day. The day honored the 43 Americans who died in the two-day Japanese air attack of 1942. The Aleutian World War II National Historic Area Visitors Center opened that same month.
The first public school in Unalaska opened in 1883, one of the developments that followed the American purchase of Alaska. Others included a Methodist mission and orphanage. The islands also became headquarters for a considerable fleet of revenue cutters, which patrolled the sealing grounds of the Pribilof Islands.
In 1924, the U.S. Congress extended American citizenship to all Native Americans. The law has been held to include the indigenous peoples of Alaska. In 1933 the U.S. Bureau of Indian Affairs built a hospital in Unalaska.
From 1965 to 1971, the United States conducted underground nuclear weapons tests on Amchitka Island as part of the Vela Uniform program. The final detonation, code-named Cannikin, was the largest underground nuclear explosion the country ever set off.
The Alaska Native Claims Settlement Act became law in 1971. In 1977, the Ounalashka Corporation, from Unalaska, declared a dividend. It was the first village corporation to declare and pay one to its shareholders.
The Aleutian Islands were designated a UNESCO biosphere reserve in 1976. In June 2017, the U.S. government asked to withdraw 17 biosphere reserves from the program, and the Aleutians were among them.
The 2020 U.S. census recorded 7,152 people on the islands. Of those, 4,254 lived in Unalaska, the main settlement.
The native people call themselves Unangan, though most non-natives know them as the Aleut. Their language is one of two main branches of the Eskimo-Aleut family, which is not known to be related to any other language family.
Sheep and reindeer were once believed practicable on the less mountainous islands. Sheep raising seems to have faded with the advent of synthetic fibers, which lowered the value of wool. There are bison on islands near Sand Point. During the 1980s, some llamas were raised on Unalaska.
Today the economy rests mainly on fishing and the presence of the U.S. military. The only crop is potato. Chickens are raised in barns, protected from the cold.
Getting around depends on partial air service and on ferries. The Alaska Marine Highway passes through many of the American islands.
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Common questions
What does Unangam Tanangin mean?
It is the native name for the Aleutian Islands and means land of the Aleuts.
Why does the chain include both the westernmost and easternmost points of the United States?
The islands cross longitude 180 degrees, where east and west longitude end. By longitude, Amatignak Island is the westernmost point and Semisopochnoi Island the easternmost.
Why are there almost no trees in the Aleutians?
Winds are so strong that taller trees are vulnerable to snapping off. The few conifers on Adak and Amaknak, remnants of the Russian period, rarely reach even 10 feet.
What happened on Kiska in August 1943?
American and Canadian troops, 34,426 men in all, invaded the island. The Japanese force of 5,183 men had already left on the 28th of July without being noticed. Still, 313 Allied men died, many from accidents and accidental fire.
What was Cannikin?
Cannikin was the final detonation in the underground nuclear tests on Amchitka Island between 1965 and 1971. It was the largest underground nuclear explosion by the United States.
All sources
36 references cited across the entry
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- 7Op-Ed: U.S. Territories, Not States, Bear the Scars of World War IIDouglas W. Domenech — The Federalist — September 11, 2020
- 8JournalCrustal structure of the Bering and Chukchi shelves: Deep seismic reflection profiles across the North American continent between Alaska and RussiaS. L. Klemperer et al. — 2002
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- 10i.e. east of 172° E and west of 163° W longitude, straddling the antimeridian
- 11NewsAlaska volcano erupts again, sending up another ash cloudJanuary 26, 2017
- 12BookIsland Realm: A Pacific PanoramaIan Todd — Angus & Robertson — 1974
- 13BookAustralasiaAlfred Russel Wallace — The University of Michigan — 1879
- 14BookAmchitka and the Bomb: Nuclear Testing in AlaskaDean Kohlhoff — University of Washington Press — 2002
- 16BookArea Handbook for OceaniaJohn William Henderson — U.S. Government Printing Office — 1971
- 18JournalThe Aleutian Low, storm tracks, and winter climate variability in the Bering SeaS.N. Rodionov et al. — November 2007
- 19America's Smallest Forest?January 4, 2019
- 20Guide to Alaska TreesUnited States National Agricultural Library
- 22BookSerendipity: An Ecologist's Quest to Understand NatureJames Estes — University of California Press — 2016
- 23BookCulture and Archaeology of the Ancestral Unangax/Aleut of the Aleutian Islands, AlaskaDebra Corbett — Springer International — 2023
- 24JournalContinuity and Change in the Eastern Aleutian Archaeological SequenceRichard Davis — 2010-12-01
- 26BookCrossroads of Continents: Cultures of Siberia and AlaskaWilliam W. Fitzhugh et al. — Smithsonian Institution Press — 1988
- 30Battle of the Aleutian IslandsNovember 17, 2009
- 31When the president came to dinner: FDR in AlaskaSeptember 12, 2014
- 34BookBirds of the Aleutian Islands, AlaskaDaniel D. Gibson et al. — Nuttall Ornithological Club — 2007
- 35BookThe Russian Orthodox Church of Alaska and the Aleutian Islands and Its Relation to Native American Traditions—An Attempt at a Multicultural Society, 1794–1912Viacheslav Vsevolodovich Ivanov — Library of Congress — 1997
- 36BookArchaeological Investigations in the Aleutian IslandsWaldemar Jochelson — Carnegie Institution of Washington — 1925
- 37MagazineThe Aleutians: Alaska's Far-out IslandsLael Morgan — September 1983