Why This is North America's Most Important Lake

North America is home to so many large, prominent, and important lakes. But one lake stands well above the rest. Because this lake has a secret power. It has something in it that most people don't ever speak of, even if they know what that power is. This is a lake that created and firmly holds together one of the most important urbanized areas on the continent. And it's a lake that, were it to disappear entirely, would take an entire country down with it. So why is Lake Ontario North America's most important lake, even when its size suggests otherwise? I'm Jeff and this is the incredible and powerful story underpinning Lake Ontario. To understand Lake Ontario, you have to first look at where it sits on the map. Surrounded by the Canadian province of Ontario to the north and west, and the U.S. state of New York to the south and east, Lake Ontario is the easternmost lake in a string of connected lakes we collectively call the Great Lakes. Which means, if you head south from Lake Ontario, in a boat, you'll hit Lake Erie, where you can then travel to lakes Huron, Michigan, and Superior. These five lakes combined account for an area of more than 94,000 square miles. That's huge. In fact, that's nearly the size of the U.S. state of Oregon. But instead of endless forests, mountains, and deserts, there's just lots and lots of fresh water. Now, within the Great Lakes, Lake Ontario can feel a bit understated. If you just measure each lake by its pure surface area, Lake Ontario is the smallest by far at just 7,340 square miles. But don't let this small footprint fool you. Because while it certainly looks to be small on the map, it's not actually the smallest by volume. In fact, Lake Ontario has more than three times the amount of water as its nearest neighbor, Lake Erie, with 393 cubic miles of fresh water. Meanwhile, Lake Erie has just 116 cubic miles of fresh water. The main difference between these lakes is their depth. Where Lake Erie has an average depth of just 62 feet, Lake Ontario plunges to an average depth of 283 feet. Which means, despite its smaller size overall, it holds so much more water. And really, aside from Lake Superior, the largest of the Great Lakes, Lake Ontario is the deepest when you average it all out. Of course, all of this matters because of where Lake Ontario sits on the continent. You see, as you travel from the east coast of North America to the west, the land slowly rises. And this is the case for the Great Lakes as well. Which means, over in the far west, with Lake Superior, you're roughly at an elevation of around 600 feet above sea level. From there, water cascades down into Lake Huron, then Lake Erie, and finally a big drop over the Niagara Falls into Lake Ontario. Every single drop of water that goes into one of our four westerly Great Lakes will eventually make its way into Lake Ontario unless it's manually pulled out. Which means, geographically, Lake Ontario is the final stop before you head out to the Atlantic Ocean. That's right, the Great Lakes have a large and direct opening to the wider world. At the easternmost end of Lake Ontario sits one of North America's largest and most important rivers, the St. Lawrence River. Flowing out to the northeast, this river directly links the entirety of the Great Lakes by way of Lake Ontario to the rest of the world. Which means that a ship carrying cargo from Europe can sail directly into the mouth of the St. Lawrence River, where Quebec City is located, and sail directly into the heart of the continent, to where Toronto currently sits. And because of some ingenious engineering, that same ship can go all the way to Chicago if it really wanted to. Which means, not only is Lake Ontario the final stop for all water before it heads out the St. Lawrence River and into the ocean, but it's also the first stop for all ships heading into the Great Lakes. This is an incredible geographic advantage for Canada. Without it, moving goods from the interior cities, places like Toronto, or even as far away as Thunder Bay, would need to travel by land. Even with railroads, that's a long and arduous journey to a port on the east coast, let's say Halifax. But because Lake Ontario is directly connected to the open ocean by way of the St. Lawrence River, and because all other Great Lakes are connected to one another, this entire region is one interconnected, traversable waterway. And this has directly translated into the kind of geography that exists around Lake Ontario. You see, Lake Ontario is the most important lake in all of North America, but really only one side of it has taken advantage of that physical geography. If you look to the north, the Canadian side, you'll find Canada's largest metropolitan region, Toronto, as well as a smattering of other large cities such as Hamilton, Oshawa, and even Kingston in the far east. Meanwhile, if you look to the south, in New York State, you'll find cities like Rochester, but it's otherwise far less developed. One side is incredibly urbanized, the other is far more agricultural. And all of this boils down to Lake Ontario, a lake that has almost single-handedly propped up an entire country. But if this is the case, and Lake Ontario is so important to the entirety of North America, then why has only one side taken advantage of it? Why did Canada look at Lake Ontario and decide that was the best place for its most important Well, to answer that question, we first need to go back in time to the beginnings of human settlement on Lake Ontario. But just like the United States essentially turned its back on the strategic data of Lake Ontario and kept it largely undeveloped, millions of website owners turned their backs on their own search data, leaving their online presence completely invisible. To develop your digital geography, you need a true command center. 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You can even run a content gap analysis, where you plug in a competitor's site, and Ahrefs shows you the exact keywords they are getting traffic from that you're missing. And because AI is changing search, their new Brand Radar feature even tracks whether tools like ChatGPT, Gemini, and AI Overviews are mentioning your brand. If you want concrete answers on why a page isn't working, or what you should write next, Ahrefs is the answer. Start exploring the full platform and get serious, professional-grade intelligence on your website by going to Ahrefs.com slash free using my link in the description or the pinned comment below. Thanks to Ahrefs for supporting the show. Now let's get back to human settlement on Lake Ontario. Lake Ontario has a long and robust history of human settlement. If you can believe it, long before the very idea of Canada was ever a thing, humans still lived and used the lake in much the same way they do today. In fact, if we go all the way back to the beginnings of human history in this region, we can scientifically trace the very first people to somewhere around 11,000 years ago. And these people, much like some people still do today, hunted caribou for survival. But here's the weird thing about this particular period of time. Lake Ontario looked nothing like it does now. Over thousands of years, the lake has shifted dramatically. At periods of time, it would have held far more water than it currently does. Likewise, during drier and colder periods, when more water was trapped in ice, the lake was likely far smaller than its current footprint. All this is to say, the lake's modern water levels are theorized to have stabilized somewhere around 4,000 years ago. And it's after this period that we start to see the origins of the indigenous tribes that would become the Anishinaabe and Iroquois peoples. People who used the lake as a source of fresh water for irrigation, but also as a vast trade network, where people could sail from one end of the lake to the other in order to trade various goods. This was the period where permanent human settlements began appearing all around Lake Ontario. And those settlements grew large, even by European standards. In fact, early European explorers documented their initial interactions with these indigenous settlements, and they described them more like castles, with large fortifications, with traditional marketplaces, and longhouses that would resemble something more like an apartment building today. Suffice it to say, the pastoral picture of a small tribal village with a few tents was not really what Europeans found around Lake Ontario. Of course, those same Europeans that documented these cities would eventually bring about their downfall. Around 1615, a French explorer named Etienne Brulé found his way into Lake Ontario. He was followed by famous explorer Samuel de Champlain, who ultimately founded what would become the vast North American colony of New France. Specifically, he founded a colony he called Quebec City, at the very mouth of the St. Lawrence River. You see, Champlain, with the help of Etienne Brulé, realized something early on in European colonization. While the Spanish were occupied in Central America, and the British were busy establishing its early colonies in what would become Massachusetts and Virginia, Champlain realized that, while bitterly cold, the St. Lawrence River provided a pure and almost unobstructed pathway directly into the heart of the continent, a place that was teeming with something more valuable than gold at the time, fur. This can't be overstated enough. In the 1600s, the world was desperate for fur. And so, throughout the 1600s and 1700s, the French would go about colonizing the interior, mostly from the mouth of the St. Lawrence River and around Lake Ontario, or Lac de Saint-Louis, as it was known to the French at the time. In fact, they established Fort Frontenac in 1673 at the mouth of Lake Ontario, where modern day Kingston sits today, then Fort Niagara in 1726 in order to control the westerly access point of Lake Ontario, and finally Fort Ruy in 1759, the very place where Canada's largest city would blossom decades later. All was done so that France could continue to export vast amounts of fur to the rest of the world. At this point in time, Lake Ontario was almost entirely controlled by New France, except for one small British fort on the southern side of the lake called Fort Oswego. The British and the French have always had a contentious relationship, dating back thousands of years. So it's not a surprise that a similar rivalry would heat up in North America over who controlled what land. And Britain, seeing France's vast empire of fur growing in the north, decided that they wanted more of the action. This would eventually boil over during what we call the French and Indian War in 1754, or the North American phase of the Seven Years' War between the two countries that raged all over the world. And at the end of it, Britain took control over almost all of New France, including all of its territories and forts along Lake Ontario and the St. Lawrence River. Suddenly, the eastern half of North America was looking like a single-player game. But that wouldn't last for long. Just as Britain took New France and renamed it British Canada, another entity was welling up along its east coast colonies, the country that would become the United States. After a long and bitter war for independence, North America was carved up yet again. This time, Britain was stuck in the north, with the new country in the south. And here is where we see the beginnings of the formal divide of Lake Ontario. But that peace between these two countries wouldn't last long. Both knew and understood the value of Lake Ontario. And so, in 1812, as hostilities between the two countries flared up again, Lake Ontario became one of the primary battlefields, as controlling it meant controlling the rest of the Great Lakes. While ultimately the war would end in mostly a stalemate between the two sides, it permanently cemented the dividing border within the lake. Neither British Canada nor the United States would take control of the entirety of it. The linchpin of the entire continent would remain divided. But here's the thing. Now in 2026, the lake is easily the most important in all of North America, but only one country is really taking advantage of it. There's a secret power hidden within Lake Ontario. It's something that everyone who understands the region knows about, but also something that nobody ever speaks of. It's almost a superpower, to be honest. And it's definitely something that, if the circumstances are right, could change the power dynamics of the entire continent. You see, Lake Ontario is what we call a linchpin lake. Remember the St. Lawrence River that connects Lake Ontario and every other Great Lake to the Atlantic Ocean? Well, while parts of the St. Lawrence River are controlled by the United States, particularly the northern border of New York State, the mouth to the Atlantic Ocean is firmly Canadian. This is where Quebec City is located, which means that every good that ships from the interior of the continent by way of the Great Lakes must pass through Canadian waters. We're talking about goods and crops from states like Ohio, Michigan, Illinois, Indiana, Minnesota, and Iowa. Places with megacities like Chicago, Detroit, and even cities not directly connected but still heavily reliant on the Great Lakes like Minneapolis. All of these American states and cities are entirely reliant on Canada to sell their stuff to the world. In fact, every year, tens of millions of tons of American cargo traverses Lake Ontario, bringing in billions of dollars of revenue back to those states and the U.S. at large. And I know what you're thinking. What about the Erie Canal? Yes, the U.S. did see this issue back in the early 1800s, and they, rightfully for their own security after the War of 1812, began construction of a large canal system that would bypass Canada's geographic stranglehold on the Great Lakes. And for a long time, it worked tremendously well. In fact, the Erie Canal is largely attributed for New York State's ascendancy for over a century. But now it's 2026. Ships are much larger. And the Erie Canal, well, that's mostly used for recreational boats at this point. Most U.S. cargo, given the friendliness between the United States and Canada throughout the 1900s, opted to take the wider and deeper St. Lawrence River. And so, if you effectively block the St. Lawrence River, or the well and canal that connects Lake Erie to Lake Ontario from American shipping, the supply chain for tens of millions of people will basically stop. And this means that a large part of the United States, one of its most important regions, is completely dependent on Canada by way of Lake Ontario. Of course, such an action is highly unlikely, but the geographic lever is there. We just don't speak of it. But that brings us to another superpower that Lake Ontario holds. Of course, shipping goods to the world is one thing, but the true superpower in 2026 is shipping energy. Both countries are demanding more and more energy to power everything from our phones and laptops to vehicles and homes, and of course, all the data centers that run those things. And this has proven to be quite the boon for those who live around Lake Ontario. You see, because Lake Ontario is so much lower in elevation than Lake Erie, it sends a tremendous amount of water over a large waterfall that we call Niagara Falls. In fact, Niagara Falls is so large and powerful that it has the seventh highest flow rate in the world, with more than 5.9 million cubic feet of water flowing over its edge every single minute. And while that is certainly a lot of water, what it ultimately amounts to is a lot of energy. All told, with multiple hydroelectric power plants, the water transfer from Lake Erie to Lake Ontario generates about 4.9 gigawatts of power, or enough to power 3.8 million homes. This amount of power generation can't be overstated enough. Without it, New York would look very different, but Canada would almost be unrecognizable. You see, surrounding the western end of Lake Ontario is a place we call the Golden Horseshoe, and this is by far Canada's most important, most economically powerful, and most populated region. All told, about 1 out of every 4 Canadians, or about 11 million total, live in this tiny pocket of land, hugging Lake Ontario from its northwest end and around the bend to the southwest. This is why it's called the Golden Horseshoe because, on the map, it actually resembles a horseshoe. And this is the home of the Toronto metropolitan region, home to 7 million people by itself. It's where Canada's largest corporations sit. It's where its stock exchange handles the daily volume of trades for the entire country. It's the cultural epicenter of Canada as a whole, and it sits right along the shores of Lake Ontario. And all of this economic power would never have been possible were it not for that very same lake. The reality of Toronto and the Golden Horseshoe comes down to a very specific set of geographic circumstances enabled by Lake Ontario. For one, the vast amount of trade that flows through the Great Lakes every day brings constant capital and money into the Toronto region at large. And specifically, Hamilton Harbour, at the lake's far western end, proved to be a phenomenal port where freighters heavy with manufactured steel or fresh ore from the depths of Canada could be easily loaded up and then shipped through Lake Ontario and out to the world. But perhaps more importantly, Lake Ontario provided an amount of freshwater that single-handedly powered the Golden Horseshoe. Southern Ontario, that odd-shaped piece of land squished between Lakes Ontario, Erie, and Huron, contains some of Canada's best soil. And because of this, the entire region is highly agriculturally productive. Large cities and settlements require two primary things to grow, fresh water and food. And because of Lake Ontario, and to a lesser extent Huron and Erie, Canada's most agriculturally productive region enabled its most economically important urban region to become obscenely wealthy. And so, Lake Ontario has proven itself to be North America's most important lake. It handles a vast amount of trade from both Canada and the United States. It generates an enormous amount of electricity due to its elevation difference from its sibling lakes. And it almost single-handedly developed Toronto, one of North America's most important metropolitan regions. No other lake in North America can claim even half as much as Lake Ontario. Once again, now's your chance to get rid of those pesky ads and sponsors. Go get a full free month of our geography community at TheBite.co. You'll even get extra and exclusive articles and videos. Link is in the description below. I hope you enjoyed learning all about Lake Ontario. If you did, be sure to check out this video all about the Cayman Islands. Thanks for watching. See you next time.