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Alaska, constituent state of the United States of America. It was admitted to the union as the 49th state on January 3, 1959.

Alaska lies at the extreme northwest of the North American continent, and the Alaska Peninsula is the largest peninsula in the Western Hemisphere. Because the 180th meridian passes through the state’s Aleutian Islands, Alaska’s westernmost portion is in the Eastern Hemisphere. Thus, technically, Alaska is in both hemispheres.

Quick Facts
seal of Alaska
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Seal of Alaska
Alaska: state bird
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Alaska: state bird
Alaska: state flower
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Alaska: state flower
Capital:
Juneau
Population1:
(2020) 733,391; (2024 est.) 740,133
Governor:
Michael J. Dunleavy (Republican)
Date Of Admission:
January 3, 1959
U.S. Senators:
Lisa Murkowski (Republican)
Daniel Sullivan (Republican)
State Nickname:
The Last Frontier
State Motto:
"North to the Future"
State Bird:
willow ptarmigan
State Flower:
alpine forget-me-not
State Song:
“Alaska’s Flag”
Seats In The U.S. House Of Representatives:
1 (of 435)
Time Zone:
Alaskan (GMT − 9 hours)
Total Area (Sq Km):
1,723,337
Total Area (Sq Mi):
665,384
  1. Excluding military abroad.

Alaska is bounded by the Beaufort Sea and the Arctic Ocean to the north, Canada’s Yukon territory and British Columbia province to the east, the Gulf of Alaska and the Pacific Ocean to the south, the Bering Strait and the Bering Sea to the west, and the Chukchi Sea to the northwest. The capital is Juneau, which lies in the southeast, in the panhandle region.

Alaska is central to the great circle route connecting North America with Asia by sea and air and is equidistant from most of Asia and Europe. That central location has made Alaska militarily significant since the Japanese invasion of the Aleutians in 1942 during World War II. Alaska’s eastern border with Canada is about 1,538 miles (2,475 km) long, more than one-third the length of the entire U.S. boundary with Canada (3,987 miles [6,416 km]). Alaska’s western maritime boundary, separating the waters of the United States and Russia, was established in the Treaty of Cession of 1867 (which declared the transfer of Alaska from Russia to the United States). The roughly 1,000-mile (1,600-km) de facto boundary runs through the Chukchi Sea and the Bering Strait to a point between Alaska’s St. Lawrence Island and Russia’s Chukotskiy (Chukchi) Peninsula and to the southwest, between Attu Island, the westernmost island of the Alaskan Aleutian chain, and the Russian Komandor Islands. The boundary leaves a patch of international waters, known as the “Doughnut Hole,” in the Bering Sea. Off the extreme western end of the state’s Seward Peninsula, Little Diomede Island, part of Alaska, lies in the Bering Strait only 2.5 miles (4 km) from Russian-owned Big Diomede Island. Both Russia and the United States have shown a tacit tolerance of unintentional airspace violations, which are common in bad weather.

The name Alaska is derived from the Unangax (Aleut) word alaxsxa or alaxsxix, both meaning “mainland” or “great land.” Indeed, Alaska has an immense area and a great variety of physical characteristics. Aside from its mainland peninsula, the state includes about 15,000 square miles (38,800 square km) of fjords and inlets and about 34,000 miles (54,400 km) of indented tidal coastline. In addition, most of the continental shelf of the United States lies along Alaska’s coast. In the Alaska Range north of Anchorage is Mount McKinley (Denali), 20,310 feet (6,190 meters) high—the highest peak in North America. Nearly one-third of the state lies within the Arctic Circle, and about four-fifths of Alaska is underlain by permafrost (permanently frozen sediment and rock). Tundra—the vast treeless Arctic plains—makes up about half of the state’s surface area. The southern coast and the panhandle at sea level are fully temperate regions. In those and in the adjoining Canadian areas, however, lies the world’s largest expanse of glacial ice outside Greenland and Antarctica. Rimming the state on the south is one of Earth’s most active earthquake belts, the circum-Pacific seismic belt. Alaska has more than 130 active volcanoes, most of which are on the Aleutian Islands and the adjacent Alaska Peninsula. The Alaska earthquake of 1964 was one of the most powerful earthquakes recorded in the United States.

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Upon attaining statehood, Alaska increased the size of the United States by nearly one-fifth. The new area included vast stretches of unexplored land and untapped resources. Its settlement and exploitation have been hindered by its distance from the rest of the country and by geographic and climatic impediments to travel and communications; Alaska continues to be the country’s last frontier. About half of the state’s inhabitants live in the Greater AnchorageKenai Peninsula area.

The difficulty of finding a balance between conservation and development in an enormous land has been ongoing since the beginning of the 20th century. Alaska’s residents and the state and federal governments have had to make delicate decisions on such major issues as a natural gas pipeline project, Alaska Natives’ land claims, the creation of national parks and wildlife refuges, noncommercial whaling by Indigenous peoples, and related matters. One of the major conflicts occurred in the late 1960s and early 1970s between conservationists and petroleum companies over the proposed Trans-Alaska Pipeline, which now runs from the oil-rich North Slope on the Arctic Ocean to Valdez, in the south. The debate intensified following a catastrophic oil spill in 1989, when the tanker Exxon Valdez released some 250,000 barrels of oil into Prince William Sound. Moreover, beginning in the 1980s, the two sides came into conflict over whether to permit drilling in the Arctic National Wildlife Refuge. In the early 21st century the question of drilling in the 23-million-acre (9.3-million-hectare) National Petroleum Reserve–Alaska on the Arctic coastal plain and on the continental shelves of the Beaufort and Chukchi seas also became controversial issues. Area 665,384 square miles (1,723,337 square km). Population (2020) 733,391; (2024 est.) 740,133.

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Land of Alaska

Relief

Alaska comprises eight distinct physiographic and environmental regions. Much of the mainland panhandle region, a narrow strip of land 25 to 50 miles (40 to 80 km) wide lying east and south of the St. Elias Mountains, is composed of the Boundary Ranges. There are several large ice fields there, and the peaks include Mount St. Elias (18,008 feet [5,489 meters]), from whose summit the Alaska-Yukon border shifts due north following the 141st meridian. The western extension of that mountain chain is the Chugach Range, a giant arc at the northernmost edge of the Gulf of Alaska. Many of the range’s remote valleys and high ridges are still unexplored, and the relief and glaciation inhibit exploitation. The coast is characterized by frequent and intense oceanic storm systems that have produced dense rain forests on the coastal mountain flanks.

The region of the south coastal archipelago and the Gulf of Alaska islands includes the Alexander Archipelago in the panhandle region, with 1,100 islands, as well as Kodiak Island, just southeast of the Alaska Peninsula, and its satellites south of Cook Inlet. Those islands are lower, less rugged, and less glaciated. All receive heavy rain and are affected by waters warmed by both the Kuroshio and Alaska currents.

The Aleutian region includes the Alaska Peninsula, which forms the south shoreline of Bristol Bay, and the 1,100-mile- (1,770-km-) long Aleutian island chain that separates the North Pacific from the Bering Sea. The chain includes 14 large islands, 55 significant but smaller ones, and numerous islets. The largest islands are Unimak, Unalaska, and Umnak. On the occasionally clear summer days, active volcanoes and such glacier-covered peaks as symmetrical Shishaldin Volcano (9,372 feet [2,857 meters]) on Unimak can be seen. Usually, however, the weather is wet and stormy, the winds horizontal and cutting, and the fog all-pervading.

The broad Alaska Range region connects the Aleutian Range across the southern third of mainland Alaska to the Wrangell Mountains, which abut the vast complex of the St. Elias Mountains. The Wrangell Mountains have large active volcanoes and high valley glaciers. The flanks of that subarctic range are largely tundra-covered.

The low-lying interior basin region between the Alaska Range in the north and the Chugach–Wrangell–St. Elias mountains to the south and east enjoys a relatively temperate climate. The valleys of the Susitna and Matanuska rivers, Cook Inlet, and the Kenai Peninsula are where the majority of Alaskans live.

The central plains and lowlands of interior Alaska constitute a vast region west and north of the Alaska Range; they reach as far north as the Brooks Range. The lowlands extend west from the Canadian border to Norton Sound, the Seward Peninsula, and the Yukon River delta, as well as south to the northern rim of Bristol Bay on the Bering Sea. The region is characterized by river flats and truncated tablelands, as well as extensive areas of wetlands formed from melting permafrost. It includes Yukon Flats National Wildlife Refuge, a 9-million-acre (3.6-million-hectare) refuge that contains the Yukon Flats, a vast wetland basin, and the Tanana River floodplain, part of which supports the growth of boreal forests.

The Brooks Range runs from west to east in the area north of the interior. It gradually slopes northward through a set of low-ridge foothills to a linear coastal plain bordering the Arctic Ocean and westward to lower hills north of Kotzebue Sound. There are a few high Arctic glaciers in the eastern Brooks Range, and the area is semiarid. The lower flanks and valleys are tundra-covered, with permafrost features.

The Arctic coastal plain north of the Brooks Range, often referred to as the North Slope, has a truly polar environment, with the sea waters along the coast frozen eight months of the year and the ground permanently frozen except for a thin zone of summer melting. It is treeless and, in summer, grasses and Arctic alpine flowers abound. The Colville River flows through the centre of that region and lies along the eastern edge of the National Petroleum Reserve–Alaska, originally set aside for petroleum development. The Arctic National Wildlife Refuge lies to the east of the Colville. Prudhoe Bay, located between those reserves, is a centre of oil-drilling activities in the region.

Drainage

Because of the permanently frozen ground, the Arctic coastal plain contains countless shallow lakes that provide summer food for migratory birds. The two largest lakes in Alaska are Iliamna Lake and Becharof Lake. The major river system in Alaska is the Yukon, which originates in Canada’s Yukon territory. It receives drainage from the southern slopes of the Brooks Range, from the interior, and from the northern slopes of the Alaska Range. Its major tributary is the Tanana River.