In North America, the Western Continental Divide is an imaginary line that sits atop a continuous ridge of mountain summits that divide the continent into two main drainage areas.
Rain or melting snow on one side (via rivers and streams) flows west to the Pacific Ocean; on the other side, rivers and streams flow northeast to Hudson Bay, Canada, or southeast to the Gulf of Mexico.
The Eastern Continental Divide runs along the high ridges and peaks of the Appalachian Mountains, and it separates land draining east to the Atlantic Ocean from that draining west and southwest to the Mississippi River, and the Gulf of Mexico.
Every continent except Antarctica has a continental divide, and like North America, a few have more than one. In South America, the Continental Divide lies along the Andes Mountains.