The Arctic Ocean is the smallest, and shallowest of the world's five major oceans. It occupies a roughly circular basin and covers an area of about 14,056,000 km2 (5,427,000 sq mi), almost the size of Russia. The coastline is estimated to be 45,390 km (28,200 mi) long.
In general terms it includes Baffin Bay, Barents Sea Beauford Sea Chukchi Sea, East Siberian Sea, Greenland Sea, Hudson Bay,Kara Sea, Laptev Sea, White Sea and other tributary bodies of water. It is connected to the Pacific Ocean by the Bering Strait and to the Atlantic Ocean through the Greenland Sea and Labrador Sea.
Surrounded by the land masses of Europe, North America, Greenland, and by several islands, it is partly covered by sea ice throughout the year, and almost completely in the winter months.
The ocean is virtually icelocked from October to June, and ships are subject to superstructure icing from October to May. Before the advent of modern icebreakers, ships sailing the Arctic Ocean risked being trapped or crushed by sea ice.