What is the continental divide and why is it important?

Written by Rebecca Mathews
Published: March 11, 2023
© EQRoy/Shutterstock.com
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If you’ve heard of the continental divide but wondered what it is exactly, you’re in the right place! We’re going to answer the question, “What is the continental divide and why is it important?” We’ll examine how continental divides are made, what they do, and how they affect people and animals.

Lake of Glass - A panoramic view of clear and colorful Lake of Glass surrounded by rugged high peaks of Continental Divide on a sunny Summer day. Rocky Mountain National Park, Colorado, USA.
Continental divides are mountainous geographical features in the landscape that separate rainfall and drain it into different areas.


What Is A Continental Divide?

Continental divides are mountainous geographical features in the landscape that separate rainfall and drain it into different areas.

They are large boundaries that dictate what landmass, rivers, oceans, and in some cases, endorheic basins with no outlets to an ocean, rain or snow melt runs into.

Imagine a mountain range like the Rockies. When it rains overhead, raindrops land on either side of the highest peaks and run downhill in opposite directions. This establishes the flow of rivers and means those rainstorm droplets end up in very different places.  

Simply put, a continental divide is a water drainage divider.

Most challenging peak in the Rocky Mountains
Continental divides are mountainous geographical features in the landscape that separate rainfall.

©Nicholas Courtney/Shutterstock.com

America’s Continental Divide

America has six continental divides dictating where rainfall ends up, but when people say “the continental divide” they usually mean The Great Continental Divide, sometimes shortened to The Great Divide.

It runs for the most part, along the Rocky Mountains’ highest ridge from Cape Prince of Wales on the Bering Sea coast of Alaska, to the Strait of Magellan, in South America’s Andes.

It’s considered the greatest because it’s the longest and directs water into either the Atlantic or the Pacific ocean.

Rain that falls on the east of the continental divide eventually joins the Atlantic Ocean. It enters the South Platte River and runs through the Mississippi river, New Orleans, and into the Gulf of Mexico.

Rain falling on the western side runs in the opposite direction to the Pacific Ocean via the Colorado River. It travels through Utah, the Hoover Dam, and Las Vegas.

In some cases, water will run into an endorheic basin like Utah’s Great Salt Lake or Oregon’s Crater Lake that has no ocean outlets.

The Great Divide runs all the way from Alaska through Mexico and into South America, diverting a massive amount of rainfall and water resources. It is a huge geological feature. The highest point is Colorado’s Gray’s Peak with an elevation of 14,270 feet.

Cairns on the Great Divide Trail
Acoma and Zuni tribes built stone bridges and cairns which still stand on the Great Divide Trail.


Central and South America

In Central America, the continental divide runs alongside the Sierra Madre mountain system and the Panama Canal cuts through it. Continuing on to South America, the continental divide runs along the Andes mountain chain. Water falling to the west of the Andes reaches the Pacific ocean and to the east, it finishes in the Atlantic ocean.

How Was It Made?

Continental Plates
The Earth’s crust is formed of seven continental plates that move back and forth.


The Earth’s crust is formed of seven continental plates that move back and forth. When they rub against each another they cause earthquakes.

In the distant past, continental plates collided with enormous force, and when a small tectonic plate collided with the North American plate 70 million years ago, it was subducted (pulled beneath). This motion pushed up a towering mountain range we know today as the Great Continental Divide.

It’s staggering to think the Earth’s activity so many millions of years ago has such a profound effect on today’s ecosystems, weather patterns, droughts, and the crop harvest we rely on.

Why is it so Far West?

The continental divide known as The Great Divide is way off center, to the west of the continent. It wasn’t designed by humans, it’s an accident of geography that occurred when the world was formed.

When the United States was colonized by Europeans in the 17th and 18th centuries, the Great Divide was a marker for the unknown that lay ‘out west’, and it was a barrier to westward expansion. Lewis and Clark’s expedition crossed it at the Lehmi Pass in Montana, and settlers crossed through the South Pass in Wyoming.

Thousands of years before settlers arrived, the continental divide was inhabited by indigenous people including the Acoma and Zuni tribes whose stone bridges and cairns still stand on the Great Divide Trail. The highest peaks were sacred to the Blackfeet Nation’s creation stories. They called the peaks “mistakis, the backbone of the world”.

The United States’ Continental Divides

Continental divide
The continental divide between the European and North American continental plate in Iceland.

©Benedikt Juerges/Shutterstock.com

The North American continent contains six mountaintop divides that send water to the Atlantic, the Pacific, and the Arctic oceans, or into landlocked lakes or salt flats.

These are the divides most experts agree on:

  • Laurentian/ Northern
  • Arctic
  • St Lawrence
  • Eastern
  • Great Basin

The Great Continental Divide and Laurentian divide converge at Glacier Park’s Triple Divide Peak in Montana. It’s a popular tourist spot and so named because from here, water enters three oceans. The Pacific, the Atlantic, and the Arctic Oceans. Experts consider it North America’s ‘hydrological apex’.

Why the Continental Divide is Important

Continental divides are important because they determine where, and to whom, fresh water goes. Every living thing on our planet needs water to survive.

Groundwater creates weather patterns, rivers, and streams that irrigate crops and provide water for many habitat regions as it makes its way to the oceans.

It has also created differing cultures and ways of life due to the water resources it provides. Wide open farms that require dams and irrigation systems would look very different if shifted.

If the divide was just a few miles further to the east or west, it would significantly change the U.S. topography, weather, and landmass use as we know it.

What Animals live near the Continental Divide in North America?

Brown Bear Close Up
Always carry bear spray on the Great Divide Trail and keep your eyes peeled.

©Piotr Krzeslak/Shutterstock.com

The Great Divide Trail runs along the continental divide and it’s packed with interesting, unusual, and sometimes dangerous animals because the habitats are so varied. The trail is one of the country’s most ecologically diverse. It runs for 3,100 miles through five western states!

Habitats include tundra, coniferous forests, subalpine meadows, craggy snow-covered peaks, grassland, sagebrush, and many miles of rivers and streams all fed by rain falling east or west from the very tip of the continental divide.

It is bear country with both grizzly and black bears in residence. Always carry bear spray on the Great Divide Trail and keep your eyes peeled. Mountain lions are a rare sight, but they do live in the Rockies, as do wolves.

Beavers, yellow-bellied marmots, coyotes, snowshoe hares, pika rodents, boreal toads, and bats have all made it their home, and hikers often spot lots of ungulate species (these are hoofed animals) including deer, elk, bighorn sheep, moose and varieties of cattle.

Bald eagles soar over the mountain tops, white-tailed ptarmigan, mountain chickadee, western tanager, and many species of owls and woodpeckers are loved by birdwatchers there.

 The continental divide is a rich habitat for all species of animals.  

Does Europe Have a Continental Divide?

European Continental Divide
A marker on Rhine Main Danube canal at the European Continental Divide in Germany.

©Steve Heap/Shutterstock.com

Yes, every continent has continental divides except Antarctica, which doesn’t receive enough rainfall to flow from peaks into drainage basins.

Europe is surrounded by many seas, has many mountain ranges, and therefore many continental divides, but the main one experts agree on (and not all agree!) is the European watershed that separates the northeast bodies of water from the southwest bodies. The northwest bodies are:

  • Atlantic Ocean
  • North Sea
  • Baltic Sea
  • Arctic Sea

The southern bodies are:

  • Mediterranean Sea
  • Adriatic Sea
  • Aegean Sea
  • Black Sea
  • Caspian Sea

The Political Continental Divide

Some commentators refer to the way states tend to regularly vote either democratic or republican as a continental divide. In some cases it refers to the social differences between American and Canadians.

What Is The Continental Divide? Why Is It Important?

Let’s recap.

The Great Continental Divide is a mountain range created millions of year ago by the Earth’s continental plate activity. It runs from Alaska to the tip of South America and dictates whether rainfall runs to the Pacific or Atlantic oceans.

It’s important because it divides water resources. In turn, this creates ecological habitats and weather patterns, so the continental divide dictates where we can successfully grow crops and thrive.

In the past, the continental divide was part of the indigenous nation’s creation mythology and in the settler period, it was a massive physical barrier to westward expansion.

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About the Author

Rebecca is a professional researcher from England's south coast with special interests in the environment, particularly archaeology and plant species. She spends a lot of time rehabilitating injured wildlife and visiting Greek islands to enjoy the company of cats.

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