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The Continental Divide
The Great Divide of the Rocky Mountains
The Continental Divide of the Americas - often called the Great Divide - is the high spine of land that decides which ocean a raindrop reaches. In the United States it runs the length of the Rocky Mountains, from the Canadian border through Montana, Wyoming, Colorado, and New Mexico down to Mexico. Rain and snow falling on the western side ultimately drain to the Pacific, while water on the eastern side flows to the Atlantic by way of the Gulf of Mexico.
The divide threads along ridgelines and through high passes, and a famous long-distance path, the Continental Divide Trail, follows it for some 3,100 miles. In a few rare places the line gets strange: at Triple Divide Peak in Montana, waters part three ways - to the Pacific, the Atlantic, and Hudson Bay - and in Wyoming's Great Divide Basin the line splits around a basin that drains to no ocean at all. The marker here sits where the divide crosses the high country of the Colorado Rockies.