Most of North America is comprised of Canada and the 48 continental US states. This region is bordered by oceans and shares physical features like the Great Lakes and St. Lawrence River with Canada. The central part of the region consists of a shield and plains, with mountain ranges to the east and west. Glaciers helped form the Canadian Shield and scraped across eastern and central Canada. Major physical features include the Canadian Shield, Great Lakes, Appalachian Mountains, Rocky Mountains, and plains located between the mountain ranges.