Historic Mile 1221.8: U.S. Customs border station Port Alcan.
The Canada–United Statesborder, officially known as the International Boundary, is the longest international border in the world, shared between Canada and the United States of America, the second and fourth largest countries by area respectively. 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. Eight Canadian provinces and territories (Yukon, British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, Quebec, and New Brunswick), and thirteen U.S. states (Alaska, Washington, Idaho, Montana, North Dakota, Minnesota, Michigan, Ohio, Pennsylvania, New York, Vermont, New Hampshire, and Maine) are located along the border.
The Alaska boundary dispute (1903)
In 1903 a joint United Kingdom – Canada – U.S. tribunal established the boundary with Alaska, much of which follows the 141st meridian west.