TheLaurentian Divide also called theNorthern Divide[1] and locally theheight of land, is acontinental divide in centralNorth America that separates theHudson Baywatershed to the north from theGulf of Mexico watershed to the south and theGreat Lakes-St. Lawrence watershed to the southeast.
Water north of the divide flows to Hudson Bay; water south of the divide and also south of theSt. Lawrence Divide flows to the Gulf of Mexico, otherwise to theLabrador Sea or via the Great Lakes and St. Lawrence Seaway to theGulf of St. Lawrence.[citation needed]
From the divide's junction with theContinental Divide atTriple Divide Peak, just south of the U.S. border in northwesternMontana, it runs north to just across the border then east through southern Alberta andSaskatchewan where it turns southeasterly reentering the U.S. at the northwestern corner ofNorth Dakota. It then continues to the extreme northeast corner ofSouth Dakota before crossing the middle ofMinnesota's western border at theTraverse Gap. The divide then runs north and east through northern Minnesota, throughSuperior National Forest in the eastern tip, intoOntario. There it passes to the north ofLake Nipigon, then runs as far south as the 48th parallel before veering north again to cross the western border ofQuebec just south ofLake Abitibi. It then meanders northeasterly across Quebec to the southwestern boundary ofLabrador. From there, it follows the boundary jaggedly north toKilliniq Island where it becomes the boundary betweenNunavut and Labrador before reaching its terminus atCape Chidley on theLabrador Sea.[citation needed]
Twotriple divide points lie on the divide. One is at its origin on Triple Divide Peak, inGlacier National Park, Montana, where it meets the Continental Divide; this is usually considered the hydrological apex of North America. That peak divides the waters of theColumbia River watershed which flow to the Pacific Ocean from the waters of theNelson River watershed which flow to Hudson Bay and the Mississippi River watershed which flows to the Gulf of Mexico. The other triple divide is atHill of Three Waters[2][3] nearHibbing,Minnesota, which is the junction with the St. Lawrence divide. This is not an obvious summit, but a highland plains where the watersheds of the Mississippi, Nelson and St. Lawrence River (which flows to the Gulf of St. Lawrence) meet.[citation needed]
The eastern portion of the divide marked the original northern boundary of both Ontario and Quebec provinces at the time ofConfederation in 1867, although both have since expanded significantly northward. West of Lake Superior, the divide formed the northern boundary of the United States'Louisiana Purchase in 1803.[citation needed]
