prime meridian based at the Royal Observatory , Greenwich , in London , England , was established by Sir George Airy in 1851 . By 1884 , over two-thirds of all ships and tonnage used it as the reference meridian on their charts and maps . In October of that year , at the behest of US President Chester A. Arthur , 41 delegates from 25 nations met in Washington , D.C. , United States , for the International Meridian Conference . This conference selected the meridian passing through Greenwich as the official prime meridian due to its popularity . However , France abstained from the vote , and French maps continued to use the Paris meridian for several decades . In the 18th century , London lexicographer Malachy Postlethwayt published his African maps showing the " Meridian of London " intersecting the Equator a few degrees west of the later meridian and Accra , Ghana
International Meridian Conference
International Meridian Conference
Prime meridian (Greenwich)