What Countries Does the Prime Meridian Go Through?

What countries does the prime meridian go through?  The Prime Meridian goes through the countries of:

• United Kingdom
• France
• Spain
• Algeria
• Mali
• Burkina Faso
• Togo
• Ghana

Read on to learn more about the prime meridian and how it was established.

The prime meridian goes through eight countries and three continents.  The continents are Europe, Africa, and Antarctica.  It is the line that is zero longitude.  Longitude lines are imaginary lines that run from pole to pole.  One of the two ways to determine a location on earth is to know how far east or west you are from 0 degrees longitude.

The prime meridian also runs right through one city.  Also known as the Greenwich meridian, it runs through the Royal Observatory in Greenwich, which is in southeast London, England.  Some other cities are close to the prime meridian.  Here are a few of them:      

• Argentan, France is 00° 01’ W and Lourdes, France is 00° 03’ W
• Casp, Spain is 00° 01' W and Altea, Spain is 00 °02' W
• Mostagenem, Algeria is 0° 07’ E
• Gao, Mali is 00° 05’ W 
• Dori, Burkina Faso is 00° 02’ W and Fada-n-ourma, Burkina Faso is 00° 30' E
• Dapaong, Togo is 00° 16' E
• Accra, Volta is 00° 06' W

The prime meridian passes through Lake Volta in Ghana, so its longitude is 00°00' W.  

History of the Prime Meridian

As our civilization progressed and we had more communication and travel between countries, the need arose for a standard system of measurement.  We not only needed it for determining location, but for designating time as well.

Before 1884, there were many meridians used by different countries.  The International Meridian Conference was held in October 1884 in Washington DC.  There were 25 nations represented and the Greenwich meridian, which was already being used by about two thirds of all the ships in the world, was chosen to be zero longitude.  France and Brazil abstained from voting, and San Domingo voted against it, so the vote was 22 to 1.  France adopted the Greenwich meridian in 1911.

There are 360 degrees of longitude and these are measured from 0 to 180 degrees to the East and 0 to 180 degrees to the west.  When you are at 180 degrees east or west, you are on the International Date Line in the Pacific Ocean.  Each degree of longitude is about 69 miles apart and is divided into 60 minutes and each minute is divided into 60 seconds.  If a more exact location is needed, then the seconds are divided into tenths, hundredths, and so on.

To pinpoint a location, you also need a north or south coordinate.  Latitude works in much the same way as longitude.  It starts at the equator and there are 90 degrees mapped out until you reach the poles.  So the latitude of the North Pole would be 90°00' N and the latitude of the South Pole would be 90°00' S.  

This conference established standard time as well.  It divided the world into 24 sections which are roughly an hour apart.  All the countries that were at the conference agreed to this standardization of time zones.  The boundaries of the zones aren’t exactly perfect.  They vary a bit depending on geography and where people live.   

International Date Line

The International Date Line, or IDL, is exactly half way around the world from the prime meridian.  When a ship or a plane crosses this line, they will skip ahead one day or go back a day.  If you are traveling east, then a day, or 24 hours, is subtracted and you have the day to repeat.  If you are traveling west, then you add a day.  

This is a fixed point on the earth where the calendar date resets.  When the date changes at midnight on the International Date Line, it is 12:00 noon on the prime meridian.  The International Date Line is 180 degrees from the prime meridian.