Northern Divide

The Laurentian Divide or Northern Divide is a continental divide in North America dividing the direction of water flow in eastern and southern Canada from that of the northern Midwestern United States. The Laurentian Divide separates the river systems that flow northwards to the Arctic Ocean and Hudson Bay from those that flow southwards to the Atlantic Ocean, Caribbean Sea and Gulf of Mexico. The Laurentian Divide runs from its junction with the primary Continental Divide at Triple Divide Peak in Glacier National Park in Montana, and terminates at Cape Chidley on the Labrador Sea.

A continental divide is a drainage divide such that the drainage basin on one side of the divide feeds into one ocean or sea, and the basin on the other side either feeds into a different ocean or sea. In the Laurentian Divide, water north of the height of land flows to the Arctic Ocean by rivers to Hudson Bay or directly to the Arctic. Water south of the divide makes its way to the Atlantic Ocean by a variety of streams, including the Great Lakes and Saint Lawrence River to the east, and the Mississippi River to the Gulf of Mexico to the south. Many sources consider Hudson Bay to be part of the Atlantic Ocean, not the Arctic, which would make the Laurentian Divide a lesser divide between the seas of one ocean.

On the northeast, the divide's terminus is at Cape Chidley's Killiniq Island, on the Labrador Sea where that sea meets Hudson Strait, which connects to Hudson Bay. It cuts through eastern Canada, dips into the United States, and re-enters Canada before terminating in the Rocky Mountains in the western United States.

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