The 100th Meridian

1876 geographical survey of land west of 100th meridian
Wikimedia Commons

The U.S. Geological Survey established the 100th Meridian back in the late 19th century. It was named as such because it was one hundred degrees west of Greenwich. In the U.S., the boundary line actually denoted where the arid, desert-like climate in the west separated from the more humid east. But…