The Norwegian Sea is a marginal sea in the Arctic Ocean, northwest of Norway between the North Sea and the Greenland Sea, adjoining the Barents Sea to the northeast. In the southwest, it is separated from the Atlantic Ocean by a submarine ridge running between Iceland and the Faroe Islands. To the north, the Jan Mayen Ridge separates it from the Greenland Sea.
Unlike many other seas, most of the bottom of the Norwegian Sea is not part of a continental shelf and therefore lies at a great depth of about two kilometres on average. Rich deposits of oil and natural gas are found under the sea bottom and are being explored commercially, in the areas with sea depths of up to about one kilometre. The coastal zones are rich in fish that visit the Norwegian Sea from the North Atlantic or from the Barents Sea (cod) for spawning. The warm North Atlantic Current ensures relatively stable and high water temperatures, so that unlike the Arctic seas, the Norwegian Sea is ice-free throughout the year. Recent research has concluded that the large volume of water in the Norwegian Sea with its large heat absorption capacity is more important as a source of Norway's mild winters than the Gulf Stream and its extensions.