What is the Canada-U.S.A. border traditionally known as?
- A border guarded by the army along its full length
- A border that is closed to trade
- A border that runs only along the Great Lakes
- The world’s longest undefended border
Answer: The world’s longest undefended border
The Canada-U.S.A. border is traditionally called “the world’s longest undefended border.” Millions of Canadians and Americans cross it safely every year. The two countries are each other’s largest trading partner, and both are committed to a safe, secure and efficient frontier.
Learn more: Size, borders and population
- Canada is the second largest country on earth, at about 10 million square kilometres.
- Three oceans: the Pacific Ocean to the west, the Atlantic Ocean to the east and the Arctic Ocean to the north.
- The Canada–United States boundary runs along Canada’s southern edge.
- Canada and the U.S.A. are committed to a safe, secure and efficient border.
- The border is traditionally known as “the world’s longest undefended border.” Millions of people cross it safely every year.
- Population: about 41.8 million people (July 2026 estimate).
- Most Canadians live in cities, but many live in small towns and rural areas.