Claiming the most northern reaches of land on our planet, the High Arctic tundra of northern Greenland, or Kalaallit Nunaat as it is known locally, is a unique and fragile ecosystem. Veiled in near-darkness for as many as four months out of the year and enduring summer temperatures that seldom rise above 40°F, this ecoregion supports only plants and animals adapted to the most extreme of cold conditions. Often existing at their limits of survival, the natural assembly of this ecoregion is vulnerable to even minor disruptions.

The muskox, arctic wolf, polar bear, seals, and others of this ecoregion were heavily targeted by hunters in the past, but are mostly recuperating under new regulations. The largest National Park in the world, covering over 386,000 square miles, was established in the northernmost area of Greenland in 1974. A significant cause of concern for the ecoregion is the expected results of climate change faced by the region.

In a few areas of the northernmost coast, the ice-sheet extends all the way to the coast and the ice free land in the north of the island is concentrated only along the northeast coast. This northern area is less mountainous than that in the southern portion of the island, with some rolling hills such as at Peary Land at the extreme northeast. Peary Land is the most northernmost ice free landmass on the earth.

All except the very south part of Greenland lies above the Arctic Circle, which is located at 66.5 degrees latitude, and all such locations above the Arctic Circle is subject to midnight sun (polar day) in the summer as well as twenty-four hours of darkness (polar night) during winter months for up to six months from September through March depending upon the location.

The Arctic Circle is the southernmost latitude in the Northern Hemisphere at which the center of the sun can remain continuously above or below the horizon for twenty-four hours, which will result, at least once each year at any location within the Arctic Circle, that the center of the sun is visible at local midnight (polar day), and at least once that the center is not visible at local noon (polar night). Increasing the distance north above the Arctic Circle will result in increased periods of polar day and polar night.