Western Hemisphere

Geographic half of Earth west of the Prime Meridian.

The Western Hemisphere is the half of Earth located west of the Prime Meridian and east of the 180th meridian, with the Eastern Hemisphere making up the other half. In the United States, people often use "Western Hemisphere" to mean the Americas, but geographically it includes parts of other continents as well.

Geographically, this hemisphere covers the Americas (except for some Aleutian Islands southwest of mainland Alaska), the westernmost parts of Europe and Africa (both mainland and islands), the far eastern tip of Russia and its islands, many territories in Oceania, and a large section of Antarctica. The hemisphere's center lies in the Pacific Ocean at the intersection of the 90th meridian west and the Equator, near the Galápagos Islands, with Genovesa Island being the closest land.

Canada, at 9,984,670 square kilometers, is the largest country entirely within the Western Hemisphere. Fifteen independent countries here have no land borders with other nations: Antigua and Barbuda, the Bahamas, Barbados, Cape Verde, Cuba, Dominica, Grenada, Iceland, Jamaica, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Samoa, Tonga, and Trinidad and Tobago. Several other island territories are semi-independent, while the Dominican Republic, Ireland, and Haiti are considered divided island countries because they share land borders. Ten of Africa's 54 independent countries lie entirely in the Western Hemisphere, with Mauritania being the largest at 1,030,000 square kilometers; five more African countries are partially in it. Three of Europe's 44 independent countries are fully in the Western Hemisphere, and seven are partially there. Portugal is the only mainland European country entirely in this hemisphere, while Spain has the most mainland European land in it—though a moderate portion of Spain's population lives in the Eastern Hemisphere, as Barcelona sits east of the prime meridian. The Polynesian nations of Samoa and Tonga are fully in the Western Hemisphere, but no countries from Melanesia or Micronesia are.

The highest mountain in the Western Hemisphere is Aconcagua in Argentina's Andes, rising 6,960.8 meters. The tallest freestanding structure is Toronto's CN Tower at 553.3 meters, and the tallest building is One World Trade Center in New York City at 541.3 meters.

Some people dispute including non-American areas like Western Europe, since it clashes with the idea of the Western Hemisphere as the New World or the Americas. Under the standard geographical definition, events such as the Great Fire of London happened in the Western Hemisphere, even though they aren't part of American history. Likewise, saying Brazil was the last country in the Western Hemisphere to abolish slavery isn't technically accurate, because slavery continued in non-American parts of the hemisphere—Mauritania didn't abolish it until 1981. To better match the hemisphere with the Americas, some sources use the 20th meridian west and the 160th meridian east instead. This definition excludes all European and African mainlands but still includes some associated islands, more of eastern Russia and Oceania, and part of Antarctica. It covers all Alaskan islands but leaves out a small part of northeast Greenland. No matter which meridians you choose, there is no hemisphere that includes all of the Americas while excluding all land outside them.

Most of Antarctica's lowest temperatures have been recorded in the larger Eastern Hemisphere portion. Outside Antarctica, the Western Hemisphere's coldest reading was −69.6°C (−93.3°F) at the Klinck Automatic Weather Station in Greenland on December 22, 1991—also the lowest ever in the Northern Hemisphere. The Byrd Automatic Weather Station in the Western Hemisphere part of Antarctica recorded −64.4°C (−83.9°F) on July 18, 1985. The Eastern and Southern Hemispheres' lowest temperature, and Earth's overall record, was −89.2°C (−128.6°F) at Antarctica's Vostok Station on July 21, 1983.

The highest temperature ever recorded in the Northern and Western Hemispheres—and on Earth—was 56.7°C (134°F) in Death Valley, California, on July 10, 1913. A reading of 55.0°C (131°F) in Kebili, Tunisia, on July 7, 1931, is the second highest on Earth and the highest in the Eastern Hemisphere, though some weather historians question its accuracy. A 1922 reading of 58°C (136.4°F) in El Azizia, Libya, was long considered the world record before the World Meteorological Organization reassessed it.

Quick Facts

Largest country: Canada at 9,984,670 km²
Highest mountain: Aconcagua at 6,960.8 m / 4.33 mi
Tallest building: One World Trade Center at 541.3 m / 1,776 ft
Highest temperature: 56.7°C in Death Valley, California
Lowest temperature outside antarctica: -69.6°C in Greenland

Facts from the source article.

Lore & Background

The Western Hemisphere comprises the Americas, except some of the Aleutian Islands to the southwest of the Alaskan mainland; the westernmost parts of Europe and Africa, both mainland and islands; the extreme eastern tip of the Russian mainland and islands (North Asia); many territories in Oceania; and a large part of Antarctica. The center of the Western Hemisphere on the surface of the Earth is 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°19′N 89°57′W. The largest country entirely in the Western Hemisphere is Canada at 9,984,670 km2. Fifteen independent countries entirely in the Western Hemisphere have no land borders to other countries: Antigua and Barbuda, the Bahamas, Barbados, Cape Verde, Cuba, Dominica, Grenada, Iceland, Jamaica, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Samoa, Tonga and Trinidad and Tobago. Ten of Africa's 54 independent countries are entirely in the Western Hemisphere: the largest is Mauritania at 1,030,000 km2. Portugal is the only mainland European country entirely in the Western Hemisphere, and Spain has the most mainland European land in the Western Hemisphere. The highest mountain in the Western Hemisphere is Aconcagua, in the Andes of Argentina, at 6,960.8 metres (22,837 feet). The tallest building in the Western Hemisphere is One World Trade Center, in New York City, at 1,776 feet (541.3 m).

Reader's Guide

The Western Hemisphere's definition is sometimes controversial, since it conflicts with constructs that correlate it with the New World or the Americas. Under the accepted geographical definition, historical events such as The Great Fire of London (51.51°N 0.09°W) are considered to have occurred in the Western Hemisphere, despite not being events associated with the history of the Americas. Temperature records: the highest temperature ever recorded on earth is 56.7°C (134°F) in Death Valley, California on July 10, 1913, also the highest in the Northern Hemisphere and Western Hemisphere. Outside of Antarctica, the lowest temperature ever recorded in the Western Hemisphere was −69.6°C (−93.3°F) at the Klinck Automatic Weather Station in Greenland on December 22, 1991, also the lowest in the Northern Hemisphere. In the fauna of the Americas, distinct evolutionary lineages evolved in geographic isolation, including xenarthrans (anteaters, armadillos, sloths), New World monkeys, hummingbirds (over 300 species), and New World vultures. Human settlement: modern humans reached West Africa (Ivory Coast, Senegal) roughly 150,000 years ago, the Americas roughly 15,000 years ago, and Iceland and the Faroe Islands over 1,000 years ago. Some areas were uninhabited before the Age of Discovery, including Ascension Island, Cape Verde, the Galápagos Islands, and Saint Helena.