The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about 106,460,000 km2 (41,100,000 sq mi). It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Europe and Asia from the "New World" of the Americas in the European perception of the World.
Extent of the Atlantic Ocean according to the 2002 IHO definition, excluding Arctic
|Basin countries||List of bordering countries (not drainage basin), ports|
|Surface area||106,460,000 km2 (41,100,000 sq mi)|
North Atlantic: 41,490,000 km2 (16,020,000 sq mi),
South Atlantic 40,270,000 km2 (15,550,000 sq mi)
|Average depth||3,646 m (11,962 ft)|
|Max. depth||Puerto Rico Trench|
8,376 m (27,480 ft)
|Water volume||310,410,900 km3 (74,471,500 cu mi)|
|Shore length1||111,866 km (69,510 mi) including marginal seas|
|Islands||List of islands|
|Trenches||Puerto Rico; South Sandwich; Romanche|
|Settlements||A Coruña, Aracaju, Atlantic City, Bahía Blanca, Banjul, Bata, Benguela, Boston, Cabinda City, Cape Town, Casablanca, Charleston, Conakry, Dakar, Daytona Beach, Florianópolis, Freetown, Galway, Halifax, La Rochelle, Libreville, Lisbon, Luanda, Maceió, Malabo, Mar del Plata, Miami, Monrovia, Montevideo, Natal, New York City, Nouakchott, Palm Beach, Plymouth, Pointe-Noire, Porto, Rabat, Recife, Reykjavík, Rio de Janeiro, Salvador, Sligo, St. John's, Swakopmund, Swansea, Tangier, Vigo, Virginia Beach, Vitória, Wilmington|
|1 Shore length is not a well-defined measure.|
The Atlantic Ocean occupies an elongated, S-shaped basin extending longitudinally between Europe and Africa to the east, and the Americas to the west. As one component of the interconnected World Ocean, it is connected in the north to the Arctic Ocean, to the Pacific Ocean in the southwest, the Indian Ocean in the southeast, and the Southern Ocean in the south (other definitions describe the Atlantic as extending southward to Antarctica). The Atlantic Ocean is divided in two parts, by the Equatorial Counter Current, with the North(ern) Atlantic Ocean and the South(ern) Atlantic Ocean at about 8°N.
Scientific explorations of the Atlantic include the Challenger expedition, the German Meteor expedition, Columbia University's Lamont-Doherty Earth Observatory and the United States Navy Hydrographic Office.