The almost perfect circle (the earth is anoblatespheroid that is wider around the equator), drawn with a line, demarcating the Eastern and Western Hemispheres must be an arbitrarily decided and published convention, unlike theequator (an imaginary line encirclingEarth, equidistant from itspoles), which divides theNorthern andSouthern hemispheres. Theprime meridian at 0°longitude and theantimeridian, at 180° longitude, are the conventionally accepted boundaries, since they divide eastern longitudes from western longitudes. This convention was established in 1884 at theInternational Meridian Conference held inWashington, D.C. where thestandard time concepts ofCanadian railroad engineer SirSandford Fleming were adopted. The Hemispheres agreed do not correspond with exact continents. Portions ofWestern Europe,West Africa,Oceania, and extreme northeasternRussia are in the Western Hemisphere, divorcing it from the continents which form the touchstone for most geopolitical constructs of "the East" and "the West".
Consequently, meridians of20°W and the diametrically opposed160°E are often used outside of matters of physics and navigation,[1][2] which includes all of the European and African mainlands, but also includes a small portion of northeastGreenland (typically reckoned as part ofNorth America) and excludes more of eastern Russia and Oceania (e.g.,New Zealand). Prior to the global adoption of standard time, numerousprime meridians were decreed by various countries where time was defined by local noon (thereby, local).
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.
