Background: The Pacific Ocean is the largest of the world's five oceans (followed by the Atlantic Ocean, Indian Ocean, Southern Ocean, and Arctic Ocean). Strategically important access waterways include the La Perouse, Tsugaru, Tsushima, Taiwan, Singapore, and Torres Straits.The decision by the International Hydrographic Organization in the spring of 2000 to delimit a fifth ocean, the Southern Ocean, removed the portion of the Pacific Ocean south of 60 degrees south.

Geographic coordinates: 0 00 N, 160 00 W

Map reference: Political Map of the World

Area
Note:
Comparative: about 15 times the size of the US; covers about 28% of the global surface; almost equal to the total land area of the world

Coastline: 135,663 km

Climate: planetary air pressure systems and resultant wind patterns exhibit remarkable uniformity in the south and east; trade winds and westerly winds are well-developed patterns, modified by seasonal fluctuations; tropical cyclones (hurricanes) may form south of Mexico from June to October and affect Mexico and Central America; continental influences cause climatic uniformity to be much less pronounced in the eastern and western regions at the same latitude in the North Pacific Ocean; the western Pacific is monsoonal - a rainy season occurs during the summer months, when moisture-laden winds blow from the ocean over the land, and a dry season during the winter months, when dry winds blow from the Asian landmass back to the ocean; tropical cyclones (typhoons) may strike southeast and east Asia from May to December

Terrain: surface dominated by two large gyres (broad, circular systems of currents), one in the northern Pacific and another in the southern Pacific; in the northern Pacific, sea ice forms in the Bering Sea and Sea of Okhotsk in winter; in the southern Pacific, sea ice from Antarctica reaches its northernmost extent in October; the ocean floor in the eastern Pacific is dominated by the East Pacific Rise, while the western Pacific is dissected by deep trenches, including the Mariana Trench, which is the world's deepest at 10,924 m

Elevation
Mean depth: -2,970 m
Lowest point: Challenger Deep in the Mariana Trench -10,924 m
Highest point: sea level

Natural resources: oil and gas fields, polymetallic nodules, sand and gravel aggregates, placer deposits, fish

Natural hazards: surrounded by a zone of violent volcanic and earthquake activity sometimes referred to as the 'Pacific Ring of Fire'; subject to tropical cyclones (typhoons) in southeast and east Asia from May to December (most frequent from July to October); tropical cyclones (hurricanes) may form south of Mexico and strike Central America and Mexico from June to October (most common in August and September); cyclical El Nino/La Nina phenomenon occurs in the equatorial Pacific, influencing weather in the Western Hemisphere and the western Pacific;ships subject to superstructure icing in extreme north from October to May; persistent fog in the northern Pacific can be a maritime hazard from June to December

Geography
Note: the major chokepoints are the Bering Strait, Panama Canal, Luzon Strait, and the Singapore Strait; the Equator divides the Pacific Ocean into the North Pacific Ocean and the South Pacific Ocean; dotted with low coral islands and rugged volcanic islands in the southwestern Pacific Ocean; much of the Pacific Ocean's rim lies along the Ring of Fire, a belt of active volcanoes and earthquake epicenters that accounts for up to 90% of the world's earthquakes and some 75% of the world's volcanoes

Environment
Current issues: pollution (such as sewage, runoff from land and toxic waste); habitat destruction; over-fishing; climate change leading to sea level rise, ocean acidification, and warming; endangered marine species include the dugong, sea lion, sea otter, seals, turtles, and whales; oil pollution in Philippine Sea and South China Sea

Country name
Etymology: named by Portuguese explorer Ferdinand MAGELLAN during the Spanish circumnavigation of the world in 1521; encountering favorable winds upon reaching the ocean, he called it Mar Pacifico, which means peaceful sea in both Portuguese and Spanish

Ports and terminals
Major seaport: Bangkok (Thailand), Hong Kong (China), Kao-hsiung (Taiwan), Los Angeles (US), Manila (Philippines), Pusan (South Korea), San Francisco (US), Seattle (US), Shanghai (China), Singapore, Sydney (Australia), Vladivostok (Russia), Wellington (NZ), Yokohama (Japan)

Disputes international: some maritime disputes (see littoral states)