The Saint Lawrence River Divide is a

continental divide A continental divide is a drainage divide on a continent 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, or else is endorheic, not ...

in central and eastern

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

that separates the

Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lakes ...

St. Lawrence River The St. Lawrence River (french: Fleuve Saint-Laurent, ) is a large river in the middle latitudes of North America. Its headwaters begin flowing from Lake Ontario in a (roughly) northeasterly direction, into the Gulf of St. Lawrence, connecting ...

Basin from the southerly

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

watersheds. Water, including rainfall and snowfall, lakes, rivers and streams, north and west of the divide, drains into the Gulf of St. Lawrence or the

Labrador Sea The Labrador Sea (French: ''mer du Labrador'', Danish: ''Labradorhavet'') is an arm of the North Atlantic Ocean between the Labrador Peninsula and Greenland. The sea is flanked by continental shelf, continental shelves to the southwest, northwest, ...

; water south and east of the divide drains into the

(east of the

Eastern Continental Divide The Eastern Continental Divide, Eastern Divide or Appalachian Divide is a hydrographic divide in eastern North America that separates the easterly Atlantic Seaboard watershed from the westerly Gulf of Mexico watershed. The divide nearly span ...

, ECD) or

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...

(west of the ECD). The divide is one of six continental divides in North America that demarcate several watersheds that flow to different gulfs, seas or oceans.

Course

The divide has its origin at ‘ Hill of Three Waters’

triple divide A triple divide or triple watershed is a point on the Earth's surface where three drainage basins meet. A triple divide results from the intersection of two drainage divides. Triple divides range from prominent mountain peaks to minor side pea ...

on the

Laurentian Divide The Laurentian Divide also called the Northern Divide and locally the ''height of land'', is a continental divide in central North America that separates the Hudson Bay watershed to the north from the Gulf of Mexico watershed to the south and the ...

approx. 2 miles north of

Hibbing, Minnesota Hibbing is a city in Saint Louis County, Minnesota, United States. The population was 16,214 at the 2020 census. The city was built on mining the rich iron ore of the Mesabi Iron Range and still relies on that industrial activity today. At th ...

. It follows a ridge south of the shore of

Lake Superior Lake Superior in central North America is the largest freshwater lake in the world by surface areaThe Caspian Sea is the largest lake, but is saline, not freshwater. and the third-largest by volume, holding 10% of the world's surface fresh wa ...

, and then follows the ridge between the

Wisconsin River The Wisconsin River is a tributary of the Mississippi River in the U.S. state of Wisconsin. At approximately 430 miles (692 km) long, it is the state's longest river. The river's name, first recorded in 1673 by Jacques Marquette as "Meskousi ...

and Fox River watersheds. From there it swoops south of

Lake Michigan Lake Michigan is one of the five Great Lakes of North America. It is the second-largest of the Great Lakes by volume () and the third-largest by surface area (), after Lake Superior and Lake Huron. To the east, its basin is conjoined with that o ...

and

Lake Erie Lake Erie ( "eerie") is the fourth largest lake by surface area of the five Great Lakes in North America and the eleventh-largest globally. It is the southernmost, shallowest, and smallest by volume of the Great Lakes and therefore also has t ...

along several

recessional moraines A moraine is any accumulation of unconsolidated debris (regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice shee ...

such as the

Valparaiso Moraine The Valparaiso Moraine is a recessional moraine (a land form left by receding glaciers) that forms an immense U around the southern Lake Michigan basin in North America. It is the longest moraine. It is a band of hilly terrain composed of glac ...

and Wabash Moraine. It then crosses into the

Allegheny Plateau The Allegheny Plateau , in the United States, is a large dissected plateau area of the Appalachian Mountains in western and central New York, northern and western Pennsylvania, northern and western West Virginia, and eastern Ohio. It is divide ...

and into upper

New York New York most commonly refers to: * New York City, the most populous city in the United States, located in the state of New York * New York (state), a state in the northeastern United States New York may also refer to: Film and television * '' ...

, where it runs southeast of the St. Lawrence River, dipping briefly below

Lake Champlain , native_name_lang = , image = Champlainmap.svg , caption = Lake Champlain-River Richelieu watershed , image_bathymetry = , caption_bathymetry = , location = New York/Vermont in the United States; and Quebec in Canada , coords = , type = , ...

before running northeasterly following the western border of

Maine Maine () is a state in the New England and Northeastern regions of the United States. It borders New Hampshire to the west, the Gulf of Maine to the southeast, and the Canadian provinces of New Brunswick and Quebec to the northeast and north ...

and

Quebec Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...

. It continues into the Notre-Dame Mountains in Quebec, then turns southeasterly through central

New Brunswick New Brunswick (french: Nouveau-Brunswick, , locally ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. It is the only province with both English and ...

. From there, the divide runs easterly along the northern coast of

Nova Scotia Nova Scotia ( ; ; ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. Nova Scotia is Latin for "New Scotland". Most of the population are native Eng ...

Cape Canso Cape Canso is a headland located at the eastern extremity of the Nova Scotia peninsula in the Canadian province of Nova Scotia Nova Scotia ( ; ; ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime ...

Hydrology

The hydrology of the Great Lakes-St. Lawrence basin is elaborate: Lake Nipigon drains via the Nipigon River, the primary tributary of Lake Superior, into Nipigon Bay in central northern Lake Superior.

drains from its eastern end southeast via the St. Mary's River into Lake Huron; hydrologically, Lake Michigan is one with Lake Huron through the wide

Straits of Mackinac The Straits of Mackinac ( ; french: Détroit de Mackinac) are the short waterways between the U.S. state of Michigan's Upper and Lower Peninsulas, traversed by the Mackinac Bridge. The main strait is wide with a maximum depth of , and connects ...

at the northern end; the southwestern portion of Lake Michigan drains via the Chicago Drainage Canal into the Illinois River thence to the Gulf of Mexico. Lake Huron drains through its southern tip southerly via the St. Clair River into Lake St. Clair then southerly via the Detroit River into western Lake Erie. Lake Erie drains northerly from its northeastern end via the Niagara River into the southwestern end of Lake Ontario. Lake Ontario drains northeasterly from its northeastern end into the St. Lawrence River, and thence into the Gulf of St. Lawrence. Finally, much of the coastal and central Labrador region, especially via

Lake Melville Lake Melville is an estuary of Hamilton Inlet (itself an extension of Groswater Bay) on the Labrador coast of the Canadian province of Newfoundland and Labrador. Comprising and stretching inland to Happy Valley-Goose Bay, it forms part of the l ...

, drains to the Labrador Sea.

Canals

Four canals cross the divide: The Champlain Canal connects

to the

Hudson River The Hudson River is a river that flows from north to south primarily through eastern New York. It originates in the Adirondack Mountains of Upstate New York and flows southward through the Hudson Valley to the New York Harbor between N ...

watershed. The

Erie Canal The Erie Canal is a historic canal in upstate New York that runs east-west between the Hudson River and Lake Erie. Completed in 1825, the canal was the first navigable waterway connecting the Atlantic Ocean to the Great Lakes, vastly reducing t ...

connects

to the

watershed. The Chicago Sanitary and Ship Canal crosses the

Chicago Portage The Chicago Portage was an ancient portage that connected the Great Lakes waterway system with the Mississippi River system. Connecting these two great water trails meant comparatively easy access from the mouth of the St Lawrence River on the At ...

and connects

to the

Mississippi River The Mississippi River is the second-longest river and chief river of the second-largest drainage system in North America, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it f ...

watershed. The

Portage Canal The Portage Canal was built to connect the Fox River and Wisconsin River at Portage, Wisconsin along the Fox-Wisconsin Waterway. For a time, it completed a route from the north Atlantic Ocean, through the St. Lawrence Seaway and down the Missi ...

connects the Fox River to the

Portage, Wisconsin Portage is a city in and the county seat of Columbia County, Wisconsin, Columbia County, Wisconsin, United States. The population was 10,581 at the 2020 census making it the largest city in Columbia County. The city is part of the Madison, Wiscon ...

. Historically there were additional canals, e.g., the

Ohio and Erie Canal The Ohio and Erie Canal was a canal constructed during the 1820s and early 1830s in Ohio. It connected Akron with the Cuyahoga River near its outlet on Lake Erie in Cleveland, and a few years later, with the Ohio River near Portsmouth. It also ...

, but most of these are no longer in operation.

Locations

References

{{reflist Geographic coordinate lists Geography of the United States Drainage divides Drainage basins of North America Saint Lawrence River