Twelve states border Canada: Alaska, Washington, Idaho, Montana, North Dakota, Minnesota, Wisconsin, Michigan, New York, Vermont, New Hampshire, and Maine.
It is the longest undefended border in the world, and the international boundary is 5,527-mile (8,895-km) long.
It is also the world’s longest un-militarized border.
The present border originated with the Treaty of Paris in 1783, which ended the war between Great Britain and the separating colonies which would form the United States.
In 2000, the United States was the world’s third largest country, with more than 281 million people.
China, with 1.3 billion people, and India, with 1 billion people, are much larger in population.
In land area the United States is the fourth largest country, after Russia, Canada, and China.