Geography of the World's Oceans

An ocean is a large body of water that is saline. Oceans are a major component of the Earth's hydrosphere and cover 71% of the Earth's surface. Although the oceans of the Earth are all connected and are truly one "World Ocean," most often the world is divided into five different oceans.

The following list is arranged by size.

Great barrier reef
Great Barrier Reef in the Pacific Ocean. Peter Adams / Getty Images

The Pacific Ocean is by far the world's largest ocean at 60,060,700 square miles (155,557,000 sq km). According to the CIA World Factbook, it covers 28% of the Earth and is equal in size to nearly all of the land area on the Earth. The Pacific Ocean is located between the Southern Ocean, Asia and Australia and the Western Hemisphere. It has an average depth of 13,215 feet (4,028 m) but its deepest point is the Challenger Deep within Mariana Trench near Japan. This area is also the deepest point in the world at -35,840 feet (-10,924 m). The Pacific Ocean is important to geography not only because of its size but it has been a major historical route of exploration and migration. More »

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Atlantic Ocean

Miami coast
Atlantic Ocean seen from Miami, Florida. Luis Castaneda Inc. / Getty Images

The Atlantic Ocean is the world's second-largest ocean with an area of 29,637,900 square miles (76,762,000 sq km). It is located between Africa, Europe, the Southern Ocean and the Western Hemisphere. It includes the includes other water bodies such as the Baltic Sea, Black Sea, Caribbean Sea, Gulf of Mexico, Mediterranean Sea and the North Sea. The average depth of the Atlantic Ocean is 12,880 feet (3,926 m) and the deepest point is the Puerto Rico Trench at -28,231 feet (-8,605 m). The Atlantic Ocean is important to the world's weather (as are all oceans) because strong Atlantic hurricanes are known to develop off the coast of Cape Verde, Africa and move toward the Caribbean Sea from August to November.

Indian Ocean
Meeru Island, southwest of India, in the Indian Ocean. mgokalp / Getty Images

The Indian Ocean is the world's third-largest ocean and it has an area of 26,469,900 square miles (68,566,000 sq km). It is located between Africa, the Southern Ocean, Asia and Australia. The Indian Ocean has an average depth of 13,002 feet (3,963 m) and the Java Trench is its deepest point at -23,812 feet (-7,258 m). The waters of the Indian Ocean also include water bodies such as the Andaman, Arabian, Flores, Java and Red Seas as well as the Bay of Bengal, Great Australian Bight, Gulf of Aden, Gulf of Oman, Mozambique Channel and the Persian Gulf. The Indian Ocean is known for causing the monsoonal weather patterns that dominate much of southeast Asia and for having waters that have been historical chokepoints. More »

Southern Ocean
McMurdo Station, Ross Island, Antarctica. Yann Arthus-Bertrand / Getty Images

The Southern Ocean is the world's newest and fourth-largest ocean. In the spring of 2000, the International Hydrographic Organization decided to delimit a fifth ocean. In doing so, boundaries were taken from the Pacific, Atlantic and Indian Oceans. The Southern Ocean extends from the coast of Antarctica to 60 degrees south latitude. It has a total area of 7,848,300 square miles (20,327,000 sq km) and an average depth ranging from 13,100 to 16,400 feet (4,000 to 5,000 m). The deepest point in the Southern Ocean is unnamed but it is in the south end of the South Sandwich Trench and has a depth of -23,737 feet (-7,235 m). The world's largest ocean current, the Antarctic Circumpolar Current moves east and is 13,049 miles (21,000 km) in length. More »

Polar Bear Arctic
A Polar bear is seen on sea ice in Spitsbergen, Svalbard, Norway. Danita Delimont / Getty Images

The Arctic Ocean is the world's smallest with an area of 5,427,000 square miles (14,056,000 sq km). It extends between Europe, Asia and North America and most of its waters are north of the Arctic Circle. Its average depth is 3,953 feet (1,205 m) and its deepest point is the Fram Basin at -15,305 feet (-4,665 m). Throughout most of the year, much of the Arctic Ocean is covered by a drifting polar icepack that is an average of ten feet (three meters) thick. However, as the Earth's climate changes, the polar regions are warming and much of the icepack melts during the summer months. In terms of geography, the Northwest Passage and the Northern Sea Route have been important areas of trade and exploration. More »