The Western Hemisphere is the half of the planet Earth that lies west of the Prime Meridian—which crosses Greenwich, London, England—and east of the 180th meridian.[1] The other half is called the Eastern Hemisphere. Geo-politically, the term Western Hemisphere is often used as a metonym for the Americas or the "New World", even though geographically the hemisphere also includes parts of other continents.
The Western Hemisphere consists of the Americas, excluding some of the Aleutian Islands to the southwest of the Alaskan mainland; the westernmost portions of Europe and Africa, both mainland and islands; the extreme eastern tip of the Russian mainland and islands (North Asia); numerous territories in Oceania; and a large portion of Antarctica.
The center of the Western Hemisphere is located in the Pacific Ocean at the intersection of the 90th meridian west and the Equator, among the Galápagos Islands. The nearest land is Genovesa Island at 0.3167°N -146°W.
The highest mountain in the Western Hemisphere is Aconcagua in the Andes of Argentina at 6960.8m (22,837.3feet).[2]
The tallest freestanding structure in the Western Hemisphere is the CN Tower in Toronto at 553.3m (1,815.3feet) and the tallest building in the Western Hemisphere is One World Trade Center in New York City at 541.3m (1,775.9feet).
In an attempt to match the Western Hemisphere more closely with the Americas, some sources use the 20th meridian west and the diametrically opposed 160th meridian east to define the hemisphere.[3] This definition excludes all of the European and African mainlands, but still includes some islands associated with these continents, more of eastern Russia and Oceania, and part of Antarctica. It includes all islands of Alaska, but excludes a small portion of northeast Greenland. There is no hemisphere that includes all of the Americas while excluding all land outside of it, regardless of the meridians or points chosen to define it.
Below is a list of the sovereign states in both the Western and Eastern hemispheres on the IERS Reference Meridian, in order from north to south:
Below is a list of additional sovereign states which are in both the Western and Eastern hemispheres along the 180th meridian, in order from north to south. (France is not listed below due to its inclusion above, though the meridian does pass Wallis and Futuna.) With the exception of the United States (due to Wake Island, Guam and the Northern Mariana Islands), all of them are located on just one side of the International Date Line, which curves around them.
The following countries and territories lie outside the Americas yet are entirely, mostly, or partially within the Western Hemisphere:
Cape Verde
Gambia
Guinea
Guinea-Bissau
Liberia
Mauritania
Morocco
Saint Helena, Ascension and Tristan da Cunha
Senegal
Sierra Leone
Western Sahara
Burkina Faso
Ghana
Mali
Algeria
Togo
South Georgia and the South Sandwich Islands
Faroe Islands
Gibraltar
Iceland
Portugal
Ireland
Spain
United Kingdom
France
American Samoa
Cook Islands
French Polynesia
Niue
Samoa
Tokelau
Tonga
Kiribati
Wallis and Futuna
Fiji
Tuvalu