One major landform that is found in both the united states and canada is

The Appalachian Mountains, Rocky Mountains, and the Great Plains are all shared by the US and Canada.

The Appalachian Mountain range stretches from Newfoundland to Alabama. The Rocky Mountains runs through the western part of North America into Canada up to Alaska. Lastly the area between the two mountain ranges is referred to as the Great Plains and this region begins in the US and stretches up to Canada.