continental divide-An imaginary geographic line defined by the fact that water poured on one side of it would ultimately flow into the ocean on one side of a continent, while water poured on the other side of the line would flow into the ocean on the other side of the continent.
In North America, the continental divide is located in the Rocky Mountains.
# North America has four continental divides:
* The Great Divide, also called the Continental Divide separates the watersheds of the Pacific Ocean from those of the Atlantic or Arctic Oceans. It runs from the Seward Peninsula in Alaska, through western Canada along the crest of the Rocky Mountains to New Mexico. From there, it follows the crest of Mexico's Sierra Madre Occidental and extends to the tip of South America. It is crossed by the Panama Canal.
* The Northern Divide, or Laurentian Divide, separates the watershed of the Atlantic Ocean from that of the Arctic Ocean.
* The St. Lawrence Seaway Divide separates the Great Lakes Basin from the rest of the Atlantic Ocean watershed. Two canals cross the divide: The Chicago Sanitary and Ship Canal crosses the Chicago Portage and connects Lake Michigan to the Mississippi River watershed. The Erie Canal connects Lake Erie to the Hudson River watershed.
* The Eastern Continental Divide separates the watershed of the Gulf of Mexico from the Atlantic Ocean. It runs from northern Pennsylvania down the Appalachian Mountains to the tip of Florida, dividing the Atlantic from the Gulf of Mexico. The city of Atlanta sits atop this divide.