Lake Ontario

Lake Ontario (French: Lac Ontario) is one of the five Great Lakes of North America. It is bounded on the north, west, and southwest by the Canadian province of Ontario, and on the south and east by the U.S. state of New York. The Canada–United States border spans the centre of the lake. On the Canadian side, the major cities are Kingston, Mississauga, Toronto, Hamilton, and St. Catharines. On the American side, the major cities are Rochester and Watertown.

The last in the Great Lakes chain, Lake Ontario serves as the outlet to the Atlantic Ocean via the Saint Lawrence River, comprising the western end of the Saint Lawrence Seaway. Its primary inlet is the Niagara River from Lake Erie. The Long Sault control dam, primarily along with the Moses-Saunders Power Dam regulates the water level of the lake.

The name Ontarí'io is most often translated from Huron as "beautiful lake", but 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, with a volume of 393 cubic miles (1,640 km³). 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 massive glaciers during the last ice age. These glaciers carved out soft rocks, creating the lake’s deep basin. As the glaciers moved, they pushed material southward, forming features like small hills and ridges both on land and under the lake.

When the glaciers finally moved 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, which happens every eleven minutes. Usually, these waves are small, but they can grow bigger because of weather changes or earthquakes. Even though the lake is very deep, parts of it can freeze in winter, covering from 10% to 90% of the surface, depending on how cold it gets. In very cold winters, like in 1877 and 1878, almost the whole lake could freeze.

When cold winds blow over the warmer 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 over twenty feet of snow in a single winter! This also affects areas farther inland, like Syracuse, which often gets a lot of snow.

Fog can sometimes form in the fall, making it tricky for boats. The lake’s winds also 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, and many big wetlands are protected. However, these wetlands are changing because the natural ups and downs of the water level have been controlled. When water levels stay the same, it makes it harder for some plants to grow, especially in meadow marshes. This can lead to other plants, like cattails, taking over and reducing the variety of plants.

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, which has hurt forest birds, caused some fish to disappear, and increased dirt flowing into the lake. By the 1960s and 1970s, pollution caused green, slimy growths called algal blooms in the summer, which harmed fish and left ugly piles along the shore.

Human history

The name Ontario comes from the Huron word Ontarí'io, meaning "great lake." In old times, 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, like Lac de St. Louis and Lac Frontenac. 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, with 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. They sit on top of strong rock that is found all around the area. There are also some islands in the northwestern part of the lake. Some well-known islands include Amherst Island, Association Island, Big Island, Galloo Island, Garden Island, Grenadier Island, Howe Island, Little Galloo Island, Nicholson Island, Simcoe Island, the Toronto Islands (a group of 15 smaller islands), Waupoos Island, and Wolfe Island.

Navigation

The Great Lakes Waterway links Lake Ontario to the Atlantic Ocean through the Saint Lawrence Seaway. It also connects to other rivers and lakes using the Welland Canal and leads to Lake Erie. For pleasure boats, the Trent-Severn Waterway links 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 dot 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 special protected area covering 1,722 square miles in the southeastern part of Lake Ontario. It was designated on September 6, 2024, to safeguard historic shipwrecks and areas important for cultural, historical, and spiritual reasons for the Native American peoples of the Haudenosaunee Confederacy. The sanctuary is managed together by the National Oceanic and Atmospheric Administration's Office of National Marine Sanctuaries and the Government of New York.

Economic impact

Lake Ontario has many important ports, such as the Port of Toronto and the Port of Hamilton. The area around Hamilton Harbour is known for making steel.

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

In the past, the Great Lakes had large fisheries, but now fishing is only for fun.