The Canadian Shield is an area of exposed Precambrian rocks located in Eastern, East-Central and Northeastern Canada and the Northwestern United States. The Canadian Shield encircles Hudson Bay and stretches from the Great Lakes to the Arctic Ocean.
The Canadian Shield covers a huge area of about 54,000 square miles. It is also known as the Laurentian Plateau or the Precambrian Shield and is the oldest part of the North American plate. It is the greatest area of exposed Precambrian rock on Earth and contains fossils of algae and bacteria that are more than 2 billion years old. The shield is covered in part by boreal forests in the south.