longest border

The Canada – United States border, officially known as the International Boundary, is the longest border in the world. The terrestrial boundary (including small portions of maritime boundaries on the Atlantic, Pacific, and Arctic coasts, as well as the Great Lakes) is 8,891 kilometres (5,525 mi) long, including 2,475 kilometres (1,538 mi) shared with Alaska. It is Canada's only land border, and Canada is by far the largest nation having a land border with only one country.