Lake Ontario in the context of "Don River (Ontario)"

The St. Lawrence River (French: Fleuve Saint-Laurent, pronounced [flœv sɛ̃ lɔʁɑ̃]) is a large international river in the middle latitudes of North America connecting the Great Lakes to the North Atlantic Ocean. Its waters flow in a northeasterly direction from Lake Ontario to the Gulf of St. Lawrence, traversing Ontario and Quebec in Canada and New York in the United States. A section of the river demarcates the Canada–U.S. border.

As the primary drainage outflow of the Great Lakes Basin, the St. Lawrence has the second-highest discharge of any river in North America (after the Mississippi River) and the 16th-highest in the world. The estuary of the St. Lawrence is often cited by scientists as the largest in the world. Significant natural landmarks of the river and estuary include the 1,864 river islands of the Thousand Islands, the endangered whales of Saguenay–St. Lawrence Marine Park, and the limestone monoliths of the Mingan Archipelago.

The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes spanning the Canada–United States border. The five lakes are Superior, Michigan, Huron, Erie, and Ontario (though hydrologically, Michigan and Huron are a single body of water, joined at the Straits of Mackinac). The Great Lakes Waterway enables modern travel and shipping by water among the lakes. The lakes connect ultimately to the Atlantic Ocean via the Saint Lawrence River as their primary drainage outflow. The lakes are also connected to the Mississippi River basin through the Illinois Waterway.

The Great Lakes are the largest group of freshwater lakes on Earth by total area and the second-largest by total volume. They contain 21% of the world's surface fresh water by volume. The total surface is 94,250 square miles (244,106 km), and the total volume (measured at the low water datum) is 5,439 cubic miles (22,671 km), slightly less than the volume of Lake Baikal (5,666 cu mi or 23,615 km, 22–23% of the world's surface fresh water). Because of their sea-like characteristics, such as rolling waves, sustained winds, strong currents, great depths, and distant horizons, the five Great Lakes have long been called inland seas. Depending on how it is measured, by surface area, either Lake Superior or Lake Michigan–Huron is the second-largest lake in the world and the largest freshwater lake. Lake Michigan is the largest lake, by surface area, that is entirely within one country, the United States.

New York, also called New York State, is a state in the northeastern United States. Bordered by the New England states to the east, Canada to the north, and Pennsylvania and New Jersey to the south, its territory extends into both the Atlantic Ocean and the Great Lakes. New York is the fourth-most populous state in the United States, with nearly 20 million residents, and the 27th-largest state by area, with a total area of 54,556 square miles (141,300 km).

New York has a varied geography. The southeastern part of the state, known as Downstate, encompasses New York City, the most populous city in the United States; Long Island, with approximately 40% of the state's population, the nation's most populous island; and the cities, suburbs, and wealthy enclaves of the lower Hudson Valley. These areas are the center of the expansive New York metropolitan area and account for approximately two-thirds of the state's population. The larger Upstate area spreads from the Great Lakes to Lake Champlain and includes the Adirondack Mountains and the Catskill Mountains (part of the wider Appalachian Mountains). The east–west Mohawk River Valley bisects the more mountainous regions of Upstate and flows into the north–south Hudson River valley near the state capital of Albany. Western New York, home to the cities of Buffalo and Rochester, is part of the Great Lakes region and borders Lake Ontario and Lake Erie. Central New York is anchored by the city of Syracuse; between the central and western parts of the state, New York is prominently featured by the Finger Lakes, a popular tourist destination. To the south, along the state border with Pennsylvania, the Southern Tier sits atop the Allegheny Plateau, representing some of the northernmost reaches of Appalachia.

Toronto is the most populous city in Canada and the capital city of the Canadian province of Ontario. With a population of 2,794,356 in 2021, it is the fourth-most populous city in North America. The city is the anchor of the Golden Horseshoe, an urban agglomeration of 9,765,188 people (as of 2021) surrounding the western end of Lake Ontario, while the Greater Toronto Area proper had a 2021 population of 6,712,341. As of 2024, the Golden Horseshoe had an estimated population of 11,139,265 people while the census metropolitan area had an estimated population of 7,106,379. Toronto is an international centre of business, finance, arts, sports, and culture, and is recognized as one of the most multicultural and cosmopolitan cities in the world.

Indigenous peoples have inhabited the Toronto area, located on a broad sloping plateau interspersed with rivers, deep ravines, and urban forest, for more than 10,000 years. After the broadly disputed Toronto Purchase, when the Mississauga surrendered the area to the British Crown, the British established the town of York in 1793 and later designated it as the capital of Upper Canada. During the War of 1812, the town was captured by the United States after they won the Battle of York in 1813, after which it was largely burned down and plundered by the American troops. York was renamed and incorporated in 1834 as the City of Toronto. It was designated as the capital of the province of Ontario in 1867 during Canadian Confederation. The city proper has since expanded past its original limits through both annexation and amalgamation to its current area of 630.2 km (243.3 sq mi).

The Great Lakes Basin consists of the Great Lakes and the surrounding lands of the states of Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania, and Wisconsin in the United States, and the province of Ontario in Canada, whose direct surface runoff and watersheds form a large drainage basin that feeds into the lakes. It is generally considered to also include a small area around and beyond Wolfe Island, Ontario, at the east end of Lake Ontario, which does not directly drain into the Great Lakes, but into the Saint Lawrence River.

The Basin is at the center of the Great Lakes region.

The Thousand Islands (French: Mille-Îles, pronounced [mil il]) constitute a North American archipelago of 1,864 islands that straddles the Canada–US border in the Saint Lawrence River as it emerges from the northeast corner of Lake Ontario. They stretch for about 50 miles (80 km) downstream from Kingston, Ontario. The Canadian islands are in the province of Ontario and the U.S. islands in the state of New York.

The islands range in size from over 40 square miles (100 km) to smaller islands occupied by a single residence, or uninhabited outcroppings of rocks. To count as one of the Thousand Islands, emergent land within the river channel must have at least one square foot (0.093 m) of land above water level year-round, and support at least two living trees.

The Great Lakes Waterway (GLW) is a system of natural channels and artificial locks and canals that enable navigation between the North American Great Lakes. Although all of the lakes are naturally connected as a chain, water travel between the lakes was impeded for centuries by obstacles such as Niagara Falls and the rapids of the St. Marys River.

Its principal civil engineering works are the Welland Canal between Lakes Ontario and Erie, and the Soo Locks between Huron and Superior. Dredged channels were constructed in the St. Marys River, the Detroit River, Lake St. Clair and the St. Clair River between Huron and Erie. Usually, one or more U.S. Coast Guard icebreakers help keep the water passage open for part of the fall and early winter, although shipping usually ceases for two to three months thereafter. The St. Lawrence Seaway allows navigable shipping from the GLW to the Atlantic Ocean, while the Illinois Waterway extends commercial shipping to the Mississippi River and the Gulf of Mexico. The Great Lakes Waterway is co-administered by the governments of Canada and the United States.

The Mohawk, also known by their own name, Kanien'kehá:ka (lit. 'People of the Flint'), are an Indigenous people of North America and the easternmost nation of the Haudenosaunee, or Iroquois Confederacy (also known as the Five Nations or later the Six Nations).

Mohawk are an Iroquoian-speaking people with communities in southeastern Canada and northern New York State, primarily around Lake Ontario and the St. Lawrence River. As one of the five original members of the Iroquois Confederacy, the Mohawk are known as the Keepers of the Eastern Door who are the guardians of the confederation against invasions from the east.