What notable physical feature do the United States and Canada share?

The Great Lakes are a significant shared physical feature between the United States and Canada. These five large lakes—Superior, Michigan, Huron, Erie, and Ontario—form the largest group of freshwater lakes in the world by total area and provide critical resources such as drinking water, transportation routes, and recreational opportunities.

While the Rocky Mountains extend into both countries, they are primarily a mountain range shared by the western regions and do not span the breadth of the border in the same way as the Great Lakes. Niagara Falls, though famous and a popular natural attraction located at the border of New York and Ontario, is just one part of the larger Great Lakes system. The Mississippi River, located primarily in the United States, does not cross into Canada, making it not a shared feature.

Therefore, the Great Lakes stand out as the most significant shared physical feature, highlighting the geography and importance of water resources in both nations.