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The Shield is approximately U-shaped, with the U's points in the arctic. It covers much of Greenland; Labrador; all of Quebec north of the St. Lawrence River; much of Ontario outside the southern peninsula between the Great Lakes; the Adirondack Mountains of northern New York; parts of Michigan, Wisconsin, and Minnesota; the central portion of Manitoba away from Hudson BayHudson Bay is a large body of water in northeastern Canada. It drains a large portion of the northern areas of Ontario, Quebec and Manitoba and the southeastern area of Nunavut. A smaller offshoot of the bay, James Bay, lies to the south. The placename us and the Great PlainsThe Great Plains or High Plains are the elevated plains which lie east of the Rocky Mountains in the United States of America and Canada, covering the states of New Mexico, Texas, Oklahoma, Colorado, Kansas, Nebraska, Wyoming, Montana, South Dakota and No; northern SaskatchewanSaskatchewan ( In Detail) ( In Detail) Motto: Multis E Gentibus Vires (From many peoples, strength CapitalLargest city Regina Saskatoon Area Total % fresh water 7th largest(5th lgst prov. 651 036 km² 9. 1% Population Total (2001) Density Ranked 6th 1 015; a small portion of north-eastern AlbertaAlberta is one of Canada's provinces. Its capital is the city of Edmonton. Other cities and towns include Banff, Calgary, Red Deer, Lethbridge and Medicine Hat. See also: List of communities in Alberta. As of 2004, the population of the province was 3,183; and the mainland northern Canadian territories to the east of a line extended north from the Saskatchewan/Alberta border ( Northwest TerritoriesA former territory in the United States is called Northwest Territory . Northwest Territories Territoires du Nord-Ouest ( In Detail) ( In Detail) Motto: None Capital Yellowknife Official Languages Chipewyan, Cree, Dogrib or Tli Cho, English, French, Gwich and NunavutNunavut ( In Detail) ( In Detail) Motto: Nunavut Sanginivut (Nunavut our strength / Our land our strength Capital Iqaluit Official Language English, French, Inuktitut, and Inuinnaqtun Area Total % fresh water 1st largest(1st lgst terr. 2 093 190 km² 7.). In total it covers approximately 8 million square kilometers.

Such a large area of exposed, old rock requires some explanation. The current layout of the Shield is one of very thin soil lying on top of the bedrockThis article is about the type of rock. Bedrock is also the name of the town in which The Flintstones lived. Bedrock is the native consolidated rock underlying the Earth's surface. Above the bedrock is usually an area of broken and weathered unconsolidate, with many bare outcrops. This arrangement was caused by glaciationA glacier is a large, long-lasting river of ice that is formed on land and moves in response to gravity. Equivalently, it is a multi-year ice accretion in mountainous terrain. The glacier fringe is the area where the glacier has recently melted. There are during the last ice age, which covered the Shield and scraped the rock clean. The multitude of rivers and lakes in the entire region is caused by the watersheds of the area being so young and in a state of sorting themselves out. The Shield was originally an area of very large mountains and much volcanic activity, but over the millennia the area was eroded to its current much flatter appearance.

Mountains have deep roots and float on the denser mantle much like an iceberg at sea. As mountains erode, their roots rise and are eroded in turn. The rocks that now form the surface of the Shield were once far below the earth's surface. The high pressures and temperatures at those depths provided ideal conditions for mineralization .

The Shield is one of the world's richest areas in terms of mineral ores. It is filled with substantial deposits of nickel, gold, silver, and copper. Throughout the north of Canada there are many mining towns extracting these minerals. The largest, and best known, is Sudbury, Ontario. Sudbury is an exception to the normal process of forming minerals in the Shield since the Sudbury Basin is believed to be an ancient meteorite impact crater.

The Shield, particularly the portion in the Northwest Territories, has recently been the site of several major diamond discoveries. The kimberlite pipes in which the diamonds are found are of relatively recent origin, and one theory of their origin suggests that the Shield was at some time in the past above a hot spot in Earth's mantle (much like the one that formed Hawaii, but under land rather than ocean). The spot lifted the surrounding landscape as the continent drifted over it, forming the pipes in various locations. The line of subsurface mountains that runs from the eastern seaboard of the United States nearly to Europe before culminating in the Challenger Seamount would, if run backwards in time, follow a path that matches what is suggested.

The Shield is also covered by vast boreal forests that support an important logging industry.