The shape of ice: Mapping North America’s glaciers

North America was created by ice, and its legacy covers the landscape
Map of North American glaciation Expand Image

Ice created the landscape of North America that we’re all familiar with — even if we might not know much about how it happened.

At the height of the last glaciation, massive ice sheets spread across what is now Canada and northerly parts of the United States. When the Earth began to warm — about 19,000 years ago — that ice started to melt, leaving behind the Tyrrell and Champlain seas and many “proglacial” lakes, including Ojibway, Algonquin and McConnell. As the landscape drained, an enormous region of plains was created — spaces that would become populated by creatures such as mammoths.

Over thousands of years, the ice sheets went through thickening and thinning processes. Today, the continent is still rebounding from the weight of those sheets when they were at their thickest, which causes sea levels to fluctuate and can leave coastal regions in distress. (See the legend for more about ice-age remnants such as moraines, eskers, nunataks and water bodies.) The history of the movement of ice can be seen plainly on the Earth’s surface.

Map of North America's glaciation Expand Image
Map: Chris Brackley/Can Geo; Glacial, lake, ocean and land extents based on data by Arthur S. Dyke.

Are you passionate about Canadian geography?

You can support Canadian Geographic in 3 ways:

Best of Canada!

This story is from the May/June 2020 Issue

Related Content

Heinrich Scherer's 1702 chart of the North Pole

People & Culture

Why the North Pole matters: An important history of challenges and global fascination

In this essay, noted geologist and geophysicist Fred Roots explores the significance of the symbolic point at the top of the world. He submitted it to Canadian Geographic just before his death in October 2016 at age 93.

  • 5167 words
  • 21 minutes

People & Culture

On thin ice: Who “owns” the Arctic?

As the climate heats up, so do talks over land ownership in the Arctic. What does Canadian Arctic Sovereignty look like as the ice melts?

  • 4353 words
  • 18 minutes


Frozen in time: The remarkable legacy of Mary Vaux, amateur glaciologist

Mary Vaux’s groundbreaking 19th-century study of B.C.’s Illecillewaet Glacier created an invaluable record of the glacier’s recession

  • 4293 words
  • 18 minutes
A fog bank moved in over an icy landscape cover in shallow pools of water.


Last bastion of ice

What the collapse of the Milne ice shelf and the loss of a rare Arctic ecosystem might teach us about a changing planet

  • 2894 words
  • 12 minutes