Answer :
St. Lawrence River, the Great Plains, and the Rocky Mountains are major landforms that both Canada and the United States of America share. You could also say the great lakes. Hope I helped. : )
Geographically the North American continent is divided into few parts in east-west direction, while the political divide of the continent is in north-south direction and it's not following the natural borders but cuts across them. The USA and Canada landforms are linked through the Appalachian Mountain Range along the east coast, the Great Plains that start from the Caribbean coast in the south and go through the heart of the continent north to the Arctic waters, and in the west it is the Rocky Mountain Range and the Cascades that are connecting the two countries geographically.
