The Atlantic Ocean borders Greenland's southeast; the Greenland Sea is to the east; the Arctic Ocean is to the north; and Baffin Bay is to the west. The nearest countries are Iceland, east of Greenland in the Atlantic Ocean, and Canada, to the west and across Baffin Bay. Greenland is the world's largest island, and is the largest dependent territory by area in the world. It also contains the world's largest national park.
The total area of Greenland measures 2,166,086 km² (836,109 square miles), of which the Greenland ice sheet covers 1,755,637 km² (677,676 square miles) (81%). The coastline of Greenland is 39,330 km (24,430 miles) long, about the same length as the Earth's circumference at the Equator.
The weight of the massive Greenlandic ice cap has depressed the central land area to form a basin lying more than 300 m [1,000 feet] below sea level.
All towns and settlements of Greenland are situated along the ice-free coast, with the population being concentrated along the Western coast. The northeastern part of Greenland, which includes sections of North Greenland and East Greenland, is not part of any municipality, but is the site of the world's largest national park, Northeast Greenland National Park.
At least four scientific expedition stations and camps had been established in the ice-covered central part of Greenland (indicated as pale blue in the map to the right), on the ice sheet: Eismitte, North Ice, North GRIP Camp and The Raven Skiway. Currently, there is a year-round station, Summit Camp, on the ice sheet, established in 1989. The radio station Jørgen Brøndlund Fjord was, until 1950, the northernmost permanent outpost in the world.
The extreme north of Greenland, Peary Land, is not covered by an ice sheet, because the air there is too dry to produce snow, which is essential in the production and maintenance of an ice sheet. If the Greenland ice sheet were to completely melt away, sea levels would rise more than 7 m (23 feet)  and Greenland would most likely become an archipelago.
Between 1989 and 1993, U.S. and European climate researchers drilled into the summit of Greenland's ice sheet, obtaining a pair of two-mile (3.2 km) long ice cores. Analysis of the layering and chemical composition of the cores has provided a revolutionary new record of climate change in the Northern Hemisphere going back about 100,000 years and illustrated that the world's weather and temperature have often shifted rapidly from one seemingly stable state to another, with worldwide consequences. The glaciers of Greenland are also contributing to global sea level rise at a faster rate than was previously believed.
In February 2006, researchers reported that Greenland's glaciers are melting twice as fast as they were five years ago. According to satellite gravity measurements, the annual loss was estimated at 216 km³/yr (52 cubic miles per year) by 2005. Between 1991 and 2006, monitoring of the weather at one location (Swiss Camp) found that the average winter temperature had risen almost 10 degrees Fahrenheit.
Other research has shown that higher snowfalls from the North Atlantic oscillation caused the interior of the ice cap to thicken by an average of 6 cm/yr between 1994 and 2005.