The Prime or Greenwich Meridian at 0 degrees.
The eastern state boundary of Idaho is at 111.05° west longitude. That's 11° west of 100° west longitude, and 149° east of 100° east longitude. The state's western boundary is 5.96° west of there.
Venezuela is a large country whose boundary, east to west, ranges from about 60 degrees west longitude to about 73 degrees west longitude.
The Aleutian Island chain of Alaska crosses the 180° meridian, the boundary between east and west longitude. So the farthest east longitude and farthest west longitude in the USA are both 180 degrees.
California has a northern border and an eastern one, but no "northeastern" border. However, the boundary between California and Nevada does appear to follow close to the meridian of 120 degrres west, for about 200 miles.
The closest Idaho ever gets to 100 degrees west longitude is along its eastern border with Wyoming, at about 111 degrees west.
East longitude puts it in the Eastern Hemisphere. West longitude puts it in the Western Hemisphere.
The 100 degrees W longitude line, also known as the Prime Meridian of the Americas, is an important line of longitude. It serves as the reference point for time zones in North and Central America. It also helps to divide the world into two hemispheres, with the Western Hemisphere to the west and the Eastern Hemisphere to the east.
The prime meridian at longitude 0° marks the eastern boundary of the Western Hemisphere The corresponding anti-meridian at Longitude 180° marks the western boundary of the Western Hemisphere. (In practical terms you could also consider the international date line to be the boundary - just not the official boundary.)
For the same reason that your lawn is not above or below ground,or something like that.Zero and 180 degrees longitude form the boundary between east and west,so they are both, and they are neither.
You can determine if your location is east or west longitude by looking at the numerical value of your longitude coordinates. If the value is positive (+) then you are in the eastern hemisphere, indicating east longitude. If the value is negative (-) then you are in the western hemisphere, indicating west longitude.
It's the boundary line between the two regions, and the zero of both.
it is in the middle of the earth longitude(east and west)