Canada–United States border

"International Boundary" redirects here. For other boundaries between nations, see border.

The border of the United States and Canada, called the Canada–United States border or officially known as the International Boundary, is the longest international border in the world shared between the same pair of countries. 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.

The Peace Arch at the border between Surrey, British Columbia, and Blaine, Washington

A Royal Canadian Mounted Police constable and a state trooper before the official ceremony commemorating the joining of the Portland–Montreal Pipe Line 1 August 1941