Posted by on Tuesday, May 24, 2016
Both Canada and the United States share the longest non-militarized border in the world. However there is a long history of disputes about the border's demarcation.
The first is Machias Seal Island and North Rock (Maine / New Brunswick), located in what is known as the "Grey Zone". The space is occupied by a Canadian lighthouse but claimed by the United States and visited by U.S. tour boats. The area is patrolled by the Canadian Coast Guard.
Next is the Strait of Juan de Fuca (Washington / British Columbia) At the mouth of the strait, both countries declared fishing zones in 1977. Each country used a mildly differing method to define an equidistant water boundary.
Yukon–Alaska dispute, Beaufort Sea (Alaska / Yukon) Canada supports an extension into the sea of the land boundary between Yukon and Alaska. The U.S. does not, but instead supports an extended sea boundary into the Canadian portion of the Beaufort Sea. Such a demarcation means that a minor portion of Northwest Territories in the polar region is claimed by Alaska, because the boundary between Northwest Territories and Yukon follows a straight north-south line into the sea.
The Northwest Passage: Canada claims the passage as part of its "internal waters" belonging to Canada, while the United States regards it as an "international strait" (a strait accommodating open international traffic). The Canadian Coast Guard and Royal Canadian Navy have commissioned a new ice breaker along with multiple offshore patrol ships to guard and patrol the waters.
Dixon Entrance (Alaska / British Columbia) contains two water areas that are mutually claimed by Canada and the U.S. A line known as the "A-B" Line was defined in a 1903 arbitration decision on the Alaska/Canada boundary. The U.S. does not recognize the "A-B" line as an official boundary, instead regarding it as allocating sovereignty over the land masses within the Dixon Entrance, with Canada's land south of the line.