The Laurentide ice sheet was a massive sheet of ice that covered hundreds of thousands of square miles, including most of Canada and a large portion of the northern United States, between ~ 90,000 and ~ 18,000 years before the present day. Its southern margin included the modern sites of New York City and Chicago.

Up to two miles thick, this ice sheet was the primary feature of the North American ice age. Its cycles of growth and melting were a decisive influence on global climate during its existence.

See also

• Canadian Shield
• Lake Agassiz