The 180th Meridian

geography · maps · earth

Opposite the Prime Meridian. If the prime meridian at 0 degrees is the starting line for measuring east and west on Earth, the 180th meridian is exactly halfway around the planet on the opposite side. Together, these two lines split Earth into two equal halves like cutting an orange in half.

Same Line, Two Names. You can call this line either 180 degrees east or 180 degrees west, and both names are correct because it's the same exact spot. Imagine standing on it and pointing in any direction, it's the farthest you can go in either direction before you'd start coming back.

Divides the Hemispheres. The 180th meridian and the prime meridian together form a great ellipse, which is a giant circle around Earth that cuts it into the Western Hemisphere and the Eastern Hemisphere. This is different from the equator, which divides Earth into Northern and Southern Hemispheres.

Part of the Grid. Geographers use meridians like this one as invisible lines on maps to help pinpoint exactly where places are on Earth using coordinates. The 180th meridian is special because it's one of the most important reference lines on every globe.