Final answer:
The Rocky Mountains are the physical region in North America that extends the furthest from north to south, covering around 3,000 miles from northern British Columbia to New Mexico.
Step-by-step explanation:
The physical region that runs the greatest distance from north to south in North America is the Rocky Mountains. This mountain range extends from northern British Columbia in Canada to New Mexico in the United States. The Rockies are a major mountain system that is part of a larger grouping of ranges known as the Western Cordillera.
The entire system covers a distance of approximately 3,000 miles, running through multiple U.S. states and Canadian provinces. It forms the Continental Divide, a significant geographic boundary that determines the flow of rivers either to the Atlantic or Pacific Oceans. This physiographic province impacts not just the earth sciences but also the climate, ecosystems, and human activities across its vast stretch.
Another major mountain range in North America is the Appalachian Mountains, impacting the development and history of the eastern United States. However, the Appalachian range does not extend as far north to south as the Rocky Mountains. The physical expanse of the Rockies makes them not only an important physical feature but also a significant historical barrier and a driver in the development of the West.