Lake Ontario facts for kids

Quick facts for kids Lake Ontario
Lake Ontario seen from the International Space Station on August 24, 2013. The cloudy yellowish substance is algae bloom.
Lake Ontario Location in Ontario
Lake Ontario bathymetric map. The deepest point is marked with "×".
Location	North America
Group	Great Lakes
Coordinates	43°42′N 77°54′W / 43.7°N 77.9°W / 43.7; -77.9
Lake type	Glacial
Native name	Niigaani-gichigami  (Ojibwe)
Etymology	Ontarí:io, a Huron (Wyandot) word meaning "great lake"
Primary inflows	Niagara River
Primary outflows	St. Lawrence River
Catchment area	24,720 sq mi (64,000 km2)
Basin countries	Canada and United States
Max. length	193 mi (311 km)
Max. width	53 mi (85 km)
Surface area	7,323 sq mi (18,970 km2)
Average depth	283 ft (86 m)
Max. depth	802 ft (244 m)
Water volume	391.4 cu mi (1,631 km3)
Residence time	6 years
Shore length1	634 mi (1,020 km) plus 78 mi (126 km) for islands
Surface elevation	243 ft (74 m)
Settlements	Toronto, Ontario Mississauga, Ontario Hamilton, Ontario Rochester, New York
1 Shore length is not a well-defined measure.

Lake Ontario is one of the five Great Lakes in North America. It sits between the Canadian province of Ontario to the north and west, and the U.S. state of New York to the south and east. The border between Canada and the United States runs right through the middle of the lake.

Many Canadian cities like Hamilton, Kingston, Mississauga, and Toronto are on its northern shore. The American city of Rochester is on its southern shore. The name "Ontario" comes from the Huron word Ontarí'io, which means "great lake."

The main river flowing into Lake Ontario is the Niagara River, which comes from Lake Erie. Lake Ontario is the last lake in the Great Lakes chain. Its water flows out into the Atlantic Ocean through the Saint Lawrence River. This river is also part of the Saint Lawrence Seaway, a system of canals and locks that allows ships to travel from the Atlantic to the Great Lakes.

Exploring Lake Ontario's Geography

Lake Ontario's drainage basin, the area of land where all water flows into the lake.

Lake Ontario is the easternmost of the Great Lakes. It is the smallest in terms of surface area, covering about 7,340 square miles (19,011 km²). However, it holds more water than Lake Erie, with a volume of 393 cubic miles (1,638 km³). It is the 13th largest lake in the world. If you include its islands, the shoreline stretches for about 712 miles (1,146 km).

As the last lake in the Great Lakes system, Lake Ontario has the lowest surface elevation. It sits about 243 feet (74 meters) above sea level. This is 326 feet (99 meters) lower than Lake Erie, its upstream neighbor. The lake is about 193 miles (311 km) long and 53 miles (85 km) wide. Its average depth is 283 feet (86 meters), but it can reach a maximum depth of 802 feet (244 meters).

The main source of water for Lake Ontario is the Niagara River. The St. Lawrence River is where the water flows out. The land area that drains into Lake Ontario, called its drainage basin, covers about 24,720 square miles (64,030 km²). Like all the Great Lakes, the water levels change throughout the year. These changes are important for the health of the lake's ecosystem and its wetlands. The lake also has important freshwater fish, but pollution and invasive species have caused problems.

• Natural Harbors and Bays: Strong winds and currents have created many natural harbors and sheltered bays. These are often found near Prince Edward County, Ontario and the eastern shores. Famous examples include Toronto Bay and Hamilton Harbour. These areas are also home to long sandy beaches, like Sandbanks Provincial Park.
• Wetlands and Wildlife: These sandy areas are often connected to large wetlands. Wetlands are important homes for many plants and animals. They also provide resting spots for birds that are migrating. Presqu'ile, on the north shore, is a very important bird resting area.
• The Bay of Quinte: A special feature of the lake is the Z-shaped Bay of Quinte. This bay separates Prince Edward County from the rest of Ontario. It also has many wetlands and supports a lot of aquatic plants and fish.

• Major Rivers Flowing In: Many rivers flow into Lake Ontario. Some of the biggest include the Niagara River, Don River, Humber River, Rouge River, Trent River, Cataraqui River, Genesee River, Oswego River, Black River, Little Salmon River, and the Salmon River.

How Lake Ontario Was Formed: Geology

The basin where Lake Ontario sits was carved out by a huge sheet of ice during the last ice age. This ice sheet, called the Wisconsin ice sheet, moved across the land and dug out the soft rocks that were already there. It followed the path of an ancient river valley.

As the ice sheet moved south, it pushed a lot of material, like dirt and rocks. This created landforms such as drumlins (oval-shaped hills), kames (mounds of sand and gravel), and moraines (ridges of debris). These landforms changed how water flowed in the whole region.

When the ice sheet started to melt and move back north, it still blocked the St. Lawrence River valley. This caused the lake's water level to be much higher than it is today. This higher lake is known as Glacial Lake Iroquois. During that time, the lake drained through what is now Syracuse, New York, into the Mohawk River, then to the Hudson River, and finally to the Atlantic Ocean. You can still see the old shorelines of Lake Iroquois today. They look like dry beaches and wave-cut hills about 10 to 25 miles (16 to 40 km) from the current shoreline.

When the ice finally moved completely out of the St. Lawrence valley, the land was much lower. For a short time, the lake actually became a bay of the Atlantic Ocean, connected to the Champlain Sea. But slowly, the land began to rise again. This is called Post-glacial rebound. It's like the land is bouncing back after the huge weight of the ice (which was about 6,500 feet or 2,000 meters thick!) was removed. The land is still rising today, about 12 inches (30 cm) per century in the St. Lawrence area. Because the ice left this area last, it's still rising the fastest there. This means the lake bed is slowly tilting southward. This causes the south shore to be flooded more, turning river valleys into bays. Both the north and south shores experience erosion, but the tilting makes it worse on the south shore.

Lake Ontario's Climate and Weather

Hamilton Harbour frozen over. Ice sheets can form along the shoreline of Lake Ontario during the winter.

Lake Ontario has a natural "sloshing" rhythm called a seiche, which happens every eleven minutes. This sloshing is usually very small, about 3/4 inch (2 cm). But it can get much bigger if there are earthquakes, strong winds, or big changes in air pressure.

Because the lake is so deep, it usually doesn't completely freeze over in winter. However, a layer of ice typically covers between 10% and 90% of the lake, depending on how cold the winter is. Ice usually forms along the shore and in shallow bays. In very cold winters, like 1877 and 1878, almost the entire lake was covered in ice. The lake has completely frozen over only five times that we know of: in 1830, 1874, 1893, 1912, and 1934.

• Lake-Effect Snow: When cold winter winds blow over the warmer water of the lake, they pick up moisture. This moisture then falls as heavy lake-effect snow on the land downwind. Since the winds usually come from the northwest, the southern and southeastern shores of the lake are known as the "snowbelt." Some areas, like between Oswego and Pulaski, can get 20 feet (600 cm) or more of snow in a winter! The Tug Hill Plateau, east of the lake, also gets a lot of snow. This makes it a popular spot for winter sports like snowmobiling and cross-country skiing.
• Impact on Farming: The lake also affects the local climate in other ways. In spring, cool lake breezes keep fruit trees from blooming too early, protecting them from late frosts. In autumn, the lake delays the first frost, allowing fruits to ripen longer. This special local climate, called a microclimate, helps grow delicate fruits. The southwest shore is a major fruit-growing area, with orchards producing Apples, cherries, pears, plums, and peaches. The Niagara Peninsula is famous for its fruit and wine production, which also extends into New York.

Lake Ontario's Wildlife and Environment

Profile of coastal wetlands for Lake Ontario

The area around the Great Lakes has many different kinds of plants and animals. Lake Ontario is especially important for its wide variety of birds, fish, reptiles, amphibians, and plants. Many of these unique species live along the shorelines, especially in sand dunes, lagoons, and wetlands.

People now understand how important wetlands are to the lake. Many of the larger wetlands are now protected areas. However, these wetlands are changing because the natural ups and downs of water levels have been reduced. Many wetland plants need low water levels to grow and reproduce. When water levels stay too stable, the wetlands can shrink and lose their variety of plants. This can also lead to too many cattails growing, which push out other native plants. Pollution can make this worse by adding extra nutrients that help fast-growing plants.

Most of the forests around the lake are deciduous forests. These are filled with trees like maple, oak, beech, ash, and basswood. In the past, a lot of these forests were cut down for farming. This caused problems like fewer forest birds, the loss of native salmon, and more dirt flowing into the lake. In some areas, over 90% of the original forests were removed. Today, efforts are being made to restore these forests, especially along streams and wetlands.

In the 1960s and 1970s, pollution in the lake caused huge algal blooms every summer. These blooms killed many fish and left smelly piles of algae and dead fish along the shores.

Water Pollution Challenges

Lake Ontario is the last lake in the Great Lakes chain, which means it receives pollution from all the other lakes. A study in 2015 found that Lake Ontario was the most environmentally stressed of the five Great Lakes. Some of the main problems include:

• Too much fertilizer from farms running into the lake.
• Overflows from old city sewage systems.
• Harmful chemicals from factories along rivers that flow into the lake.
• Pollution from big cities like Toronto, Rochester, and Hamilton.

Randle Reef, in the western part of Lake Ontario, was one of the most polluted spots. However, a big cleanup project started in 2016 and is expected to finish by 2025.

A Look at Lake Ontario's Human History

The name "Ontario" comes from the Huron word Ontarí'io, meaning "great lake." In olden times, the lake was also called Cataraqui, a French version of the Mohawk word Katarokwi.

Before Europeans arrived, the lake was a border between the Huron people and the Iroquois Confederacy. In the 1600s, the Iroquois pushed the Huron out of southern Ontario and settled the northern shores of Lake Ontario. Later, when the Iroquois left, the Anishnabeg / Ojibwa / Mississaugas moved in from the north. They kept the Iroquois name for the lake.

Some people believe that Norse explorers might have traded with Indigenous peoples on the east coast of North America. This idea comes from artifacts thought to be of Norse origin found near Sodus Bay.

A map showing where the Iroquois settlement of the north shore of Lake Ontario was in the late 1600s.

• Early European Exploration: The first European believed to have reached the lake was Étienne Brûlé in 1615. French explorers gave the lake other names. In 1632 and 1656, it was called Lac de St. Louis. In 1660, a Jesuit historian named it Lacus Ontarius. A French map from 1712 called it "Lac Frontenac" after Louis de Buade, who was the Governor General of New France.
• The Lake Monster: In the 17th century, there were stories of a creature called Gaasyendietha in the lake. It was described as a large, green creature with a long neck, similar to the Loch Ness Monster.
• Trading Posts and Forts: Both the British and French built trading posts around the lake. These included Fort Frontenac (1673), Fort Oswego (1722), and Fort Rouillé (1750). The cities around Lake Ontario are some of the oldest in the Great Lakes region. For example, Kingston, Ontario, which was once the capital of Canada, started as Fort Frontenac in 1673.
• Wars and Treaties: After the French and Indian War, the British controlled all the forts around the lake. The United States took control of the forts on their side of the lake in 1794. During the War of 1812, the British and American navies fought several battles on Lake Ontario for control. After the war, the Great Lakes were mostly demilitarized by the Rush–Bagot Treaty in 1818.

USS General Pike and HMS Wolfe getting ready for battle on September 28, 1813. This was one of many battles on Lake Ontario during the War of 1812.

• Commercial Activity: After the War of 1812, the lake became a busy place for trade. Canals were built on both sides of the border, and many lake steamers traveled across it. This activity was highest in the mid-1800s, but then railways started to take over.

Famous Swims Across the Lake

As of 2012, almost 50 people have successfully swum across Lake Ontario.

A plaque honoring Marilyn Bell, the first person to swim across Lake Ontario.

• Marilyn Bell: The first person to swim across the lake was a Canadian swimmer named Marilyn Bell. She did it in 1954 when she was just 16 years old. A park in Toronto, Marilyn Bell Park, is named after her.
• Diana Nyad: In 1974, Diana Nyad became the first person to swim across the lake against the current, going from north to south.
• Natalie Lambert: On August 28, 2007, 14-year-old Natalie Lambert from Kingston, Ontario, swam from Sackets Harbor, New York, to Kingston in less than 24 hours.
• Annaleise Carr: On August 19, 2012, 14-year-old Annaleise Carr became the youngest person to swim across the lake. She completed the 32-mile (52 km) swim from Niagara-on-the-Lake to Marilyn Bell Park in just under 27 hours.

Cities and Towns Around Lake Ontario

A very large group of cities and towns, called the Golden Horseshoe, is located on the western shores of Lake Ontario. This area includes the big cities of Toronto and Hamilton. Other important ports on the Canadian side are St. Catharines, Oshawa, Cobourg, and Kingston. About 9 million people, which is more than a quarter of Canada's population, live in the area that drains into Lake Ontario.

The American side of the lake is mostly rural, except for the city of Rochester and smaller ports like Oswego and Sackets Harbor. The city of Syracuse is about 40 miles (64 km) inland, connected to the lake by the New York State Canal System. Over 2 million people live in the American part of Lake Ontario's watershed.

Lake Ontario's beachfront in Rochester, New York. This city is the largest settlement in New York located along the lake's shoreline.

Islands of Lake Ontario

View of Stella Village on Amherst Island, one of several islands located in the lake.

Lake Ontario has several islands. The biggest one is Wolfe Island. Most of the islands are on the eastern and northeastern shores, near Prince Edward County and the lake's outlet at Kingston. There are also a few islands in the northwestern part of the lake.

Navigating Lake Ontario

A diagram showing the Montreal-Lake Ontario part of the Saint Lawrence Seaway.

The Great Lakes Waterway is a system of canals and rivers that connects Lake Ontario to the Atlantic Ocean through the Saint Lawrence Seaway. It also connects Lake Ontario upstream to the other Great Lakes via the Welland Canal and Lake Erie.

• Other Waterways:

* The Trent–Severn Waterway is for pleasure boats. It connects Lake Ontario at the Bay of Quinte to Georgian Bay (part of Lake Huron). * The Oswego Canal connects the lake at Oswego to the New York State Canal System. This system has connections to the Hudson River, Lake Erie, and Lake Champlain. * The Rideau Canal, also for pleasure boats, connects Lake Ontario at Kingston to the Ottawa River in Ottawa, Ontario.

Canal Lock 1 at the Welland Canal in Lake Ontario. This canal is part of the Great Lakes Waterway, connecting Lake Ontario with the St. Lawrence River and other Great Lakes.

• Lighthouses: Many lighthouses help guide boats on the lake. Some historic examples include:

• Scenic Trails: There are also land-based trails that follow the lake's shoreline. These include the Great Lakes Circle Tour and the Seaway Trail. These scenic road systems connect all the Great Lakes and the St. Lawrence River.

Economic Importance of Lake Ontario

Cargo ships in Oshawa Harbour.

Lake Ontario is home to several important commercial ports, such as the Port of Toronto and the Port of Hamilton. Hamilton Harbour is a major center for steel production.

The government of Ontario does not allow wind power to be generated offshore in the Canadian part of the lake.

In the past, the Great Lakes had a very large fishing industry. However, too much fishing led to its decline. Today, fishing on Lake Ontario is mainly for recreation, like sport fishing.

See also

• Charity Shoal Crater
• Glacial Lake Admiralty
• Lake Ontario Waterkeeper
• List of lakes of Ontario