Is Lake Erie Bigger Than Lake Ontario?

Yes. Lake Erie is larger than Lake Ontario. Lake Erie covers 25,667 km², while Lake Ontario covers 19,011 km². Lake Erie is about 1.35 times the size of Lake Ontario — larger by 6,656 km², about the size of Brunei. But Lake Ontario is much deeper, with greater water volume.

The Short Answer

Lake Erie and Lake Ontario are two of the five Great Lakes of North America. The Great Lakes — Superior, Huron, Michigan, Erie, and Ontario — together hold about 21% of the world's surface freshwater. Erie ranks 4th of the five by surface area; Ontario ranks 5th (smallest). Both are shared between the United States and Canada.

The two lakes are connected by Niagara Falls and the Niagara River, with Lake Erie's water flowing into Lake Ontario over the famous waterfalls. Lake Erie is about 100 m higher than Lake Ontario, which is why Niagara Falls is so dramatic.

The Real Numbers

• Lake Erie surface area: 25,667 km² (9,910 sq mi)
• Lake Ontario surface area: 19,011 km² (7,340 sq mi)
• Difference: 6,656 km² — about the size of Brunei or Lebanon
• Ratio: Lake Erie is about 1.35× the size of Lake Ontario

Depth Comparison

• Lake Erie max depth: 64 m
• Lake Erie average depth: 19 m
• Lake Ontario max depth: 244 m
• Lake Ontario average depth: 86 m

Lake Ontario is dramatically deeper. Volume:

• Lake Erie volume: 484 km³
• Lake Ontario volume: 1,640 km³

Despite being smaller by surface area, Lake Ontario holds about 3.4× more water than Lake Erie. Lake Erie is the shallowest of all the Great Lakes.

The Great Lakes

The Great Lakes formed about 10,000-14,000 years ago as glaciers from the last Ice Age retreated. They were carved out by glacial action and filled with melting glacier water. Today the Great Lakes contain about 21% of the world's surface freshwater — comparable to the Russian Lake Baikal as a single freshwater system.

Ranking by surface area: Lake Superior (82,100 km²), Lake Huron (59,600 km²), Lake Michigan (58,000 km²), Lake Erie (25,667 km²), Lake Ontario (19,011 km²).

Lake Erie

Lake Erie is bordered by Ontario (Canada), Michigan, Ohio, Pennsylvania, and New York. Major cities along Erie include Cleveland, Toledo, Buffalo, Erie (Pennsylvania), and Detroit (technically on Lake St. Clair which connects to Erie).

Erie is the warmest of the Great Lakes due to its shallow depth — sometimes reaching 24°C in summer. It also freezes over more completely than the others in winter. The lake supports significant commercial and sport fishing — especially walleye, yellow perch, and smallmouth bass.

Lake Erie has been historically heavily polluted but has recovered significantly since environmental protections began in the 1970s. The Cuyahoga River that flows into Erie famously caught fire in 1969 due to oil pollution — leading to major environmental reforms. The lake faces ongoing challenges from agricultural runoff causing toxic algae blooms.

Lake Ontario

Lake Ontario is bordered by Ontario (Canada) and New York. Major cities include Toronto (Canada's largest city), Hamilton, Rochester, and Kingston (where the lake meets the St. Lawrence River). The St. Lawrence Seaway connects Lake Ontario to the Atlantic Ocean, making Toronto an important port despite being deep in the continent.

Lake Ontario is the smallest Great Lake by surface area but among the deepest. It rarely freezes completely. The lake is the receiving body for water from the entire Great Lakes system above it — Lake Superior's water eventually flows through to Ontario via the Niagara River.

Niagara Falls

Niagara Falls is one of the world's most famous waterfalls and the only point where Lake Erie's water flows to Lake Ontario. The falls are about 51 m tall and 1,200 m wide. They generate about 2,700 MW of hydroelectricity for the US and Canada combined. Niagara Falls is the most visited waterfall in the world — about 30 million visitors annually.

The falls have receded about 11 km from their original location over the past 12,000 years, as the cascading water erodes the underlying limestone. They're still receding at about 30 cm per year, though hydroelectric diversions have slowed the rate.

Cities Along the Lakes

Major Lake Erie cities: Cleveland (370,000), Buffalo (280,000), Toledo (270,000), Detroit-area (4.3 million metro), Erie (94,000). Lake Erie's south shore has been heavily industrialized for over 150 years.

Major Lake Ontario cities: Toronto (2.9 million, 6.4 million metro — Canada's largest city), Hamilton (570,000), Rochester (200,000), Kingston (130,000). Lake Ontario's north shore is much more populated than the south shore in modern times.

Environmental Issues

Both lakes face environmental challenges. Lake Erie is particularly vulnerable to algae blooms because of its shallow depth and significant agricultural runoff from the Ohio, Michigan, and Ontario farming regions. The 2014 Toledo water crisis (when toxic algae shut down drinking water for half a million people) highlighted the severity.

Lake Ontario has cleaner water than Erie historically, but still faces issues from invasive species (sea lampreys, zebra and quagga mussels), urban runoff, and warming due to climate change. The lake is critical drinking water source for Toronto and other major cities.

Key Facts

• Lake Erie is about 1.35× the size of Lake Ontario by surface area.
• Lake Ontario holds about 3.4× more water than Lake Erie due to greater depth.
• Lake Erie is the shallowest of the Great Lakes (average 19 m).
• Lake Ontario is the smallest Great Lake by surface area but among the deepest.
• Niagara Falls connects Lake Erie to Lake Ontario, dropping water 51 m.

Fun Facts

• The Great Lakes together contain about 6 quadrillion gallons of water — enough to cover the contiguous US to a depth of 3 m.
• Lake Erie has more shipwrecks than any other Great Lake — over 2,000 documented wrecks.
• Lake Ontario's deepest point (244 m) is below sea level — the lake bottom sits in a depression below the global ocean surface.
• Toronto on Lake Ontario's north shore is North America's 4th-largest city.
• The Lake Erie shore in Cleveland was where Rock and Roll was named by DJ Alan Freed.

Climate Impact

Both lakes have significant climate impacts. Lake Erie's relatively shallow depth means its waters warm quickly in summer and cool quickly in winter. Erie's lake-effect snow can dump huge amounts of snow on cities like Buffalo (where 7 feet of snow has fallen in 5 days during major events).

Lake Ontario's deeper waters take longer to warm and cool, providing more climate moderation. Toronto experiences less extreme weather than equivalent inland Canadian cities partly due to Lake Ontario's influence. Both lakes contribute to the "Great Lakes effect" weather patterns that influence climate across northeastern North America.

Shipping and Transportation

The Great Lakes-St. Lawrence Seaway connects all five Great Lakes to the Atlantic Ocean, allowing ocean-going ships to reach Lake Erie and Lake Ontario ports. The Seaway opened in 1959 and handles about 40-50 million tons of cargo annually. Major Great Lakes cargo includes iron ore, coal, grain, and steel.

Both lakes have important shipping industries. The Welland Canal (between Lake Erie and Lake Ontario) handles ships going around Niagara Falls — a critical engineering feat allowing ships to navigate between the two lakes despite the 100m elevation difference.

The Bottom Line

Lake Erie is bigger than Lake Ontario by surface area (35% larger), but Lake Ontario is much deeper and holds more water. The two lakes are connected through Niagara Falls and serve different roles in the Great Lakes system — Erie as a shallow, warm, agriculture-influenced lake; Ontario as the deepest receiving lake before water flows out to the Atlantic via the St. Lawrence. Both are critical to North American ecology, economy, and identity — and both face ongoing environmental challenges that will shape their future. Together with the other three Great Lakes, they represent one of the world's most important freshwater resources, supporting tens of millions of people in the US and Canada. The size and depth differences between Erie and Ontario reflect their different roles in this remarkable interconnected water system. Visiting either lake offers spectacular scenery — Lake Erie's beaches and islands (especially Pelee Island in Canada and Kelleys Island in Ohio), or Lake Ontario's Toronto waterfront and the historic Thousand Islands region near where the lake meets the St. Lawrence River. Both lakes will continue to evolve in response to climate change, with rising temperatures, shifting ice patterns, and changing precipitation affecting everything from fisheries to shipping to recreational use. Their stewardship requires ongoing cooperation between the United States and Canada — a bilateral relationship strengthened over decades by the Great Lakes Water Quality Agreement and other frameworks.