Which plain is completely located in canada?

Canadian Shield covers about half of Canada. It covers about 5 million km. This plain constitutes the largest mass of exposed Precambrianrock on the face of Earth. The region, as a whole, is composed of ancient crystalline rocks whose complex structure attests to a long history of ascent and deepening, mountain building (orogeny), and erosion The Shield has had a profound effect on Canadian history, settlement and economic development.