Border control is the implementation of border controls on travel between Svalbard, which maintains a policy of free migration as a result of the Svalbard Treaty (Norwegian: Svalbard-traktaten; ) and the Schengen Area, which includes the rest of Norway. The Kingdom of Denmark also maintains a complex system of subnational countries with autonomous customs policies, since they aren’t within the European Union like the Danish mainland. These are Greenland () and the Faroe Islands (). These areas do not maintain strict immigration controls with the Schengen Area, but border controls are sporadically enforced for customs purposes. Other examples of effective internal border
Greenland southwest across Baffin Bay, and Iceland, east of Greenland in the Atlantic Ocean. Greenland also contains the world's largest national park, and it is the largest dependent territory by area in the world, as well as the fourth largest country subdivision in the world, after Sakha Republic in Russia, Australia's state of Western Australia, and Russia's Krasnoyarsk Krai, and the largest in North America. The average daily temperature of Nuuk, Greenland varies over the seasons from . The total area of Greenland is (including other offshore minor islands), of which the Greenland ice sheet covers (81%) and has a volume