Lake Ontario

Lake Ontario (French: Lac Ontario) is one of the five Great Lakes of North America. It is bordered by the Canadian province of Ontario to the north, west, and southwest, and by the U.S. state of New York to the south and east. The Canada–United States border runs through the middle of the lake.

Major cities on the Canadian side include Kingston, Mississauga, Toronto, Hamilton, and St. Catharines. On the American side, the main cities are Rochester and Watertown.

Lake Ontario is the last of the Great Lakes and flows out to the Atlantic Ocean through the Saint Lawrence River, forming part of the Saint Lawrence Seaway. Its main inlet is the Niagara River from Lake Erie. The Long Sault control dam and the Moses-Saunders Power Dam help control the lake's water level.

The name Ontarí'io comes from the Huron language and often means "beautiful lake," though other translations exist.

Geography

Lake Ontario is the easternmost and smallest of the five Great Lakes by surface area, covering 7,340 square miles (19,011 km²). However, it holds more water than Lake Erie. It is the 13th-largest lake in the world. Including its islands, the lake's shoreline stretches 712 miles (1,146 km).

Lake Ontario is the last in the Great Lakes chain and sits at the lowest elevation, 243 feet (74 m) above sea level. Its deepest point reaches 802 feet (244 m). The lake is fed mainly by the Niagara River from Lake Erie and drains into the Saint Lawrence River. Its drainage basin covers 24,720 square miles (64,030 km²). The lake supports many fish species, though challenges like overfishing and pollution affect its ecosystem.

Wind and currents have formed sandbars, creating lagoons and protected harbors, such as Toronto Bay. These areas often include wetlands that are important for plants, animals, and birds. The Bay of Quinte, shaped like a Z, is a special feature that supports many wetlands and fish. Several rivers, including the Niagara and Don Rivers, flow into Lake Ontario, and the Welland Canal also connects to the lake.

Geology

Lake Ontario’s basin was shaped by huge glaciers during the last ice age. These glaciers carved out soft rocks, making the lake’s deep basin. As the glaciers moved, they pushed material south, forming small hills and ridges on land and under the lake.

When the glaciers melted away, the land began to rise, slowly shaking off the weight of the thick ice. This rising land is still happening today, causing the lake’s water level to change and shaping the shores over time. Both the north and south shores experience erosion, but the rising land affects the south shore more strongly.

Climate

Lake Ontario has a special wave pattern called a seiche. It happens every eleven minutes. Usually, these waves are small, but they can grow bigger because of weather changes or earthquakes. In winter, parts of the lake can freeze. Sometimes almost the whole lake freezes, like in 1877 and 1878.

When cold winds blow over the lake in winter, they pick up moisture and create heavy snow along the southern and southeastern shores. This area is known as the snowbelt. Some places near the lake can get a lot of snow in a single winter. This also affects areas farther inland, like Syracuse.

Fog can sometimes form in the fall, making it tricky for boats. The lake’s winds help protect plants and fruits by delaying frost. This allows many fruits like apples, cherries, pears, plums, and peaches to grow well, especially around Rochester and the Niagara Peninsula.

Ecology

Lake Ontario is a very important home for many kinds of birds, fish, reptiles, amphibians, and plants. Many of these special animals and plants live near the shore, especially in areas like sand dunes, lagoons, and wetlands. Wetlands are very important for the lake.

Most of the forests around Lake Ontario are made up of trees like maple, oak, beech, ash, and basswood. These forests have suffered from cutting down trees.

Human history

The name Ontario comes from the Huron word Ontarí'io, meaning "great lake." Long ago, it was also called Cataraqui, a French way of saying the Mohawk word Katarokwi. People first lived around Lake Ontario about 11,000 years ago. They moved around a lot, following animals and using plants for food. The lake was between the Huron people and the Iroquois Confederacy before European settlers came.

The first European to reach the lake was Étienne Brûlé in 1615. The French called it different names over time. In the 1600s, trading posts were set up by both the British and French, such as Fort Frontenac in 1673. After the French and Indian War, the British controlled the forts around the lake. During the American Revolution, the British kept control of Lake Ontario. After the war, more European settlers began to live there.

Sailing and trade grew on Lake Ontario after the War of 1812. Many ships were built, and the lake became busy with commerce. However, by the mid-1800s, trade on Lake Ontario grew less compared to other Great Lakes because new canals and roads changed the ways people and goods moved. Some important ports stayed busy, like Oswego and Kingston.

The Frontenac was the first steamship on Lake Ontario, launched in 1816. More steamships followed, and propeller ships became common by the 1850s. Iron ships started appearing in the mid-1800s.

Many people have swum across Lake Ontario. The first was Marilyn Bell in 1954 when she was 16 years old. In 2012, Annaleise Carr, then 14, became the youngest person to swim across the lake.

Settlements

A big area called the Golden Horseshoe is along the western shores of Lake Ontario. It has cities like Toronto and Hamilton. Many ports are on the Canadian side, such as St. Catharines, Oshawa, Cobourg, and Kingston. About 9 million people live near Lake Ontario in Canada. On the American side, most areas are quiet countryside, except for Rochester and smaller ports like Oswego and Sackets Harbor. The city of Syracuse is farther inland and connects to the lake through canals. Over 2 million people live near Lake Ontario in the United States.

Ontario, Canada

• Toronto
• Mississauga
• Hamilton
• Burlington
• Oshawa
• Kingston
• Whitby
• Stoney Creek
• Grimsby
• Oakville
• St. Catharines
• Port Hope
• Cobourg
• Brighton
• Pickering
• Ajax
• Bowmanville
• Belleville
• Trenton
• Niagara-on-the-Lake

New York, United States

• Rochester
• Greece
• Irondequoit
• Webster
• Oswego
• Fair Haven
• Sackets Harbor
• Cape Vincent
• Three Mile Bay
• Wilson
• Chaumont
• Olcott
• Sodus Point

Islands

Lake Ontario has many islands. The biggest one is Wolfe Island. Most of the islands are along the eastern and northeastern shores, between Prince Edward County and the lake's outlet at Kingston. Some well-known islands include Amherst Island, Association Island, Big Island, Garden Island, Grenadier Island, Howe Island, Little Galloo Island, Nicholson Island, Simcoe Island, the Toronto Islands (a group of smaller islands), Waupoos Island, and Wolfe Island.

Navigation

The Great Lakes Waterway connects Lake Ontario to the Atlantic Ocean through the Saint Lawrence Seaway. It also links to other rivers and lakes using the Welland Canal and leads to Lake Erie. For pleasure boats, the Trent-Severn Waterway connects Lake Ontario at the Bay of Quinte to Georgian Bay, which is part of Lake Huron, via Lake Simcoe. The Oswego Canal connects the lake at Oswego to the New York State Canal System, which reaches the Hudson River, Lake Erie, and Lake Champlain. The Rideau Canal is another route for pleasure boats, connecting Lake Ontario at Kingston to the Ottawa River in downtown Ottawa, Ontario.

Several lighthouses are on the lake to help boats navigate safely. Some famous ones include:

• Braddock Point Light
• Charlotte-Genesee Lighthouse
• Gibraltar Point Lighthouse
• Oswego Harbor West Pierhead Light
• Presqu'ile Lighthouse
• Selkirk Lighthouse
• Sodus Point Light
• Stony Point Light
• Thirty Mile Point Light

There is also a land trail that follows the lake’s shoreline called the Great Lakes Circle Tour and Seaway Trail. These scenic roads connect all of the Great Lakes and the St. Lawrence River. Because the Seaway Trail is only on the U.S. side, Lake Ontario is the only Great Lake without a bi-national circle tour.

National marine sanctuary

The Lake Ontario National Marine Sanctuary is a protected area in the southeastern part of Lake Ontario. It covers 1,722 square miles. It was created on September 6, 2024, to protect historic shipwrecks and areas important to the Native American peoples of the Haudenosaunee Confederacy. The sanctuary is managed by the National Oceanic and Atmospheric Administration's Office of National Marine Sanctuaries and the Government of New York.

Economic impact

Lake Ontario has important ports like the Port of Toronto and the Port of Hamilton. The area around Hamilton Harbour is good at making steel.

The government of Ontario does not allow wind farms on the lake. This was decided after a court case with Trillium Power Wind Corporation and the Superior Court of Justice.

In the past, the Great Lakes had big fisheries, but now people only fish for fun.