The Great Lakes: Earth’s Inland Seas or Lakes of Distinction?

The Great Lakes: Are They Really Just Big Ponds, or Something More?

The Great Lakes. Just the name conjures up images of shimmering horizons and endless blue. Straddling the border between the U.S. and Canada, these giants—Superior, Michigan, Huron, Erie, and Ontario—are a defining feature of the landscape, both physically and culturally. We often hear them called “inland seas,” and you can see why. But is that really what they are? Or are they just, well, really big lakes? It’s a question with a surprisingly complex answer, and it all depends on how you look at it.

Size Matters (A Lot)

Let’s get one thing straight: these lakes are HUGE. We’re talking the largest surface freshwater system on the planet. Think about this: you could fit New York, New Jersey, and all the New England states inside their combined area. That’s over 94,000 square miles! They hold roughly 21% of the world’s surface fresh water, a mind-boggling 5,439 cubic miles. To put it another way, that’s enough water to bury the entire continental U.S. under almost ten feet! Seriously, wrap your head around that for a second.

Lake Superior, the undisputed heavyweight champ of the Great Lakes, is so vast that standing on the Wisconsin shore, you can’t even see the other side. It feels like you’re staring out at an ocean. And with depths plunging down to 1,300 feet, it’s easy to see why some call it a “freshwater ocean.” It holds more than half the water in the entire system, which is just insane.

Acting Like the Ocean

So, what makes people think of these lakes as seas? Well, for starters, they act like seas in a lot of ways.

• They’re enormous: The sheer scale creates that feeling of open water stretching to the horizon.
• Waves and currents can be treacherous: They generate serious waves, strong currents, and even rip currents. I’ve seen firsthand how quickly the lake can turn from calm to dangerous.
• Winds can be fierce: The lakes are notorious for sustained winds that whip up powerful storms. I remember one summer camping trip where we nearly had our tent blown away!
• They even have “tides”: Okay, they’re not exactly tides like you’d see in the ocean, but they do experience subtle tidal effects. And then there are seiches, those oscillating waves that can cause sudden and dramatic water level changes.

Even the EPA and many researchers sometimes refer to them as inland seas. So, it’s not just a casual observation.

But a Lake Is Still a Lake, Right?

Despite all the sea-like qualities, hydrologists often see the Great Lakes as a network of interconnected, albeit massive, lakes. Why? A few key reasons:

• Freshwater, plain and simple: Unlike the salty ocean, these lakes are filled with fresh water.
• The land plays a huge role: The surrounding land has a major influence. Rain and runoff directly impact water levels and the chemical makeup of the lakes.
• Rivers feed the beast: Countless rivers and streams flow into the Great Lakes, creating a complex system where the rivers and lakes are intertwined.

A World of Life

The Great Lakes aren’t just big puddles; they’re thriving ecosystems. They’re home to over 3,500 species of plants and animals, including a whopping 170+ kinds of fish. The wetlands, dunes, and forests along the shores create a rich and interconnected web of life.

And let’s not forget the fish! The Great Lakes support crucial fish populations that, in turn, support Indigenous communities, commercial fishing, and recreational anglers like myself. There’s nothing quite like reeling in a walleye on a summer evening.

More Than Just Pretty Water

These lakes are essential to our way of life. They provide drinking water for over 40 million people in the U.S. and Canada. They also fuel the economy, generating over 1.5 million jobs and $60 billion in wages each year. From agriculture to shipping to tourism, the Great Lakes are a vital economic engine.

So, What Are They?

Ultimately, whether you call them inland seas or just really, really big lakes, it doesn’t change the fact that the Great Lakes are special. Their vastness and sea-like characteristics are undeniable. But their freshwater nature and connection to the land make them lakes at heart. No matter what you call them, they’re a precious resource that we need to protect for generations to come. They’re more than just water; they’re a part of who we are.