The Arctic National Wildlife Refuge covers about 19,049,236 acres (79,318 km²) in northeastern Alaska, in the North Slope region. It was originally protected in 1960 by order of President Eisenhower's Secretary of the Interior, Fred A. Seaton. As part of Alaska National Interest Lands Conservation Act, the refuge was expanded by the United States Congress in 1980, through the lobbying efforts of Olaus and Mardy Murie, with the Wilderness Society.

8,000,000 acres (32,375 km²) of the Refuge are designated as "Wilderness". The 1980 expansion of the Refuge designated 1,500,000 acres (6,070 km²) of the coastal plain as the 1002 area and mandated studies of the petroleum potential and biological resources of this area. Congressional authorization is required before oil drilling may proceed in this area. The remaining 10,100,000 acres (40,873 km²) of the Refuge are designated as "Minimal Management", a category intended to maintain existing natural conditions and resource values. These areas are suitable for Wilderness designation, although there are presently no proposals to designate them as Wilderness.

There are presently no roads within or leading into the Refuge. Generally, visitors gain access to the land by airplanes, but it is also possible to reach the Refuge by boat or by walking (the Dalton Highway passes near the western edge of the Refuge).

The Arctic National Wildlife Refuge supports the greatest variety of plant and animal life of any Park or Refuge in the circumpolar arctic. There is a continuum of six different ecological zones spanning some 200 miles (300 km) north to south.

Along the northern boundary of the Refuge, barrier islands, coastal lagoons, salt marshes, and river deltas provide habitat for migratory waterbirds including sea ducks, geese, swans, and shorebirds. Fish such as dolly varden and arctic cisco are found in nearshore waters. Coastal lands and sea ice are used by caribou seeking relief from biting insects during summer, and by polar bears hunting seals and giving birth in snow dens during winter.

The arctic coastal plain stretches southward from the coast to the foothills of the Brooks Range. This area of rolling hills, small lakes, and north-flowing, braided rivers is dominated by tundra vegetation consisting of low shrubs, sedges, and mosses. Caribou travel to the coastal plain during June and July to give birth and raise their young. Migratory birds and insects flourish here during the brief arctic summer. Tens of thousands of snow geese stop here during September to feed before migrating south, and musk oxen live here year-round.

South of the coastal plain, the mountains of the eastern Brooks Range rise to over 9,000 feet (3,000 m). This northernmost extension of the Rocky Mountains marks the continental divide, with north-flowing rivers emptying into the Arctic Ocean and south-flowing rivers joining the great Yukon River. The rugged mountains of the Brooks Range are incised by deep river valleys creating a range of elevations and aspects that support a variety of low tundra vegetation, dense shrubs, rare groves of poplar trees on the north side and spruce on the south. During summer, peregrine falcons, gyrfalcons, and golden eagles build nests on cliffs. Harlequin ducks and red-breasted mergansers are seen on swift-flowing rivers. Dall sheep and wolves are active all year, while grizzly bears and arctic ground squirrels are frequently seen during summer but hibernate in winter.

The southern portion of the Arctic Refuge is within the boreal forest of interior Alaska. Beginning as predominantly treeless tundra with scattered islands of black and white spruce trees, the forest becomes progressively denser as the foothills yield to the expansive flats north of the Yukon River. Frequent forest fires ignited by lightning result in a complex mosaic of birch, aspen, and spruce forests of various ages. Wetlands and south-flowing rivers create openings in the forest canopy. Neotropical migratory birds breed here in spring and summer, attracted by plentiful food and the variety of habitats. Caribou travel here from farther north to spend the winter. Year-round residents of the boreal forest include moose, lynx, marten, wolverines, black and grizzly bears, and wolves.

ANWR is believed to contain a large supply of oil. The issue of drilling for the oil has been a debated topic for many years, and has been a political football for every sitting president since Jimmy Carter. For more information on this topic, see Arctic Refuge drilling controversy.

• The ANWR's official website