Which ocean is located entirely in the Northern Hemisphere?

The Arctic Ocean is the ocean located entirely in the Northern Hemisphere.

It surrounds the North Pole and extends southward to roughly 60° north latitude. Eurasia and North America enclose much of the basin, while the Bering Strait links it with the Pacific Ocean and the Greenland–Scotland Ridge helps define its Atlantic connection.

The Arctic Ocean is the smallest and shallowest of the five commonly recognized oceans, covering about 14.06 million square kilometers. It is also the coldest, and sea ice covers much of its surface year-round, with the greatest extent generally occurring in late winter. Its waters are strongly affected by seasonal freezing and melting, river runoff from surrounding continents, and inflows from the Atlantic and Pacific.

A common mix-up is the Southern Ocean: it surrounds Antarctica and is entirely in the Southern Hemisphere, but it is not the answer to this question. The Arctic Ocean is sometimes called the Arctic Mediterranean Sea or North Polar Sea, and some oceanographers have described it as an estuary-like extension of the Atlantic. Those alternate labels do not change its geographic position.