The Arctic, is a region located at the northern-most part of the Earth. It consists of the Arctic Ocean and all or parts of Canada, Russia, Greenland, the United states, Norway, Sweden, Finland and Iceland. The Arctic region consists of a vast, ice-covered ocean, surrounded by treeless permafrost. The area can be defined as north of the Arctic Circle (66° 33'N), the approximate limit of the midnight sun and the polar night. Alternatively, it can be defined as the region where the average temperature for the warmest month (July) is below 10 °C (50 °F); the northernmost tree line roughly follows the isotherm at the boundary of this region.
http://en.wikipedia.org/wiki/Arctic
http://en.wikipedia.org/wiki/Arctic