This article or sectionappears to contradict itselfon the definition of its subject ; its own sources (Britannica, JM Olson) indicate it is usually defined as spanning from 20W to 160E. Please see thetalk page for more information.(February 2025)
This articlemay beconfusing or unclear to readers. In particular, much of the current article is anachronic. This subject needs a more historical perspective ; the notion of Western Hemisphere is tightly linked to the widespread use ofdouble-hemisphere world maps in the 17th to 19th centuries and in this sense very similar in meaning to theNew World. Also, the Greenwhich meridian was only standard from 1884 onwards. Essentially all double-hemisphere maps use a partition of hemispheres around what is now the 20th meridian west, with most using that longitude as the prime meridian. Please helpclarify the article. There might be a discussion about this onthe talk page.(January 2025) (Learn how and when to remove this message)
In an attempt to match the Western Hemisphere more closely with the Americas, some sources use the20th meridian west and the diametrically opposed160th meridian east to define the hemisphere.[1][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 northeastGreenland. There is no hemisphere that includes all of the Americas that also excludes all land outside of it, regardless of the meridians or points chosen to define it.
Below is a list of additional sovereign states which are in both the Western and Eastern hemispheres along the180th meridian, in order from north to south. (France is not listed below due to its inclusion above, though the meridian does passWallis and Futuna.) With the exception of the United States (due toWake Island,Guam and theNorthern Mariana Islands), all of them are located on just one side of theInternational Date Line, which curves around them.
Russia, passing throughChukotka Autonomous Okrug. Its portion lying east of the 180th meridian is the only part of the country lying in the Western Hemisphere.
Kiribati, passing close toArorae. The country has both theEquator and the 180th meridian (antimeridian) crossing through its territory. It is the only country located in four hemispheres.
^abOlson, Judy M (1997), "Projecting the hemisphere", in Robinson, Arthur H; Snyder, John P (eds.),Matching the map projection to the need, Bethesda, MD: Cartography and Geographic Information Society, American Congress on Surveying and Mapping,archived from the original on 2016-03-14, retrieved2020-03-03. -"Western Hemisphere",Merriam-Webster's Geographical Dictionary (3rd ed.), Springfield, Massachusetts: Merriam-Webster, 2001, p. 1294.
