It's not quite the Senkakus, but Stephen Kelly highlights a long-festering territorial dispute between the United States and Canada:
Machias Seal Island is a 20-acre, treeless lump that sits nearly equidistant from Maine and New Brunswick. It, and the even smaller North Rock, lie in what local lobstermen call the gray zone, a 277-square-mile area of overlapping American and Canadian maritime claims.
The disagreement dates back to the 1783 Treaty of Paris that ended the Revolutionary War. The treaty assigned to the newly independent 13 colonies all islands within 20 leagues — about 70 miles — of the American shore. Since Machias Seal Island sits less than 10 miles from Maine, the American position has been that it is clearly United States soil.
But the treaty also excluded any island that had ever been part of Nova Scotia, and Canadians have pointed to a 17th-century British land grant they say proves the island was indeed part of that province, whose western portion became New Brunswick in the late 18th century.
Perhaps more important to the Canadian case, the British built a lighthouse on Machias Seal Island in 1832, which has been staffed ever since. Even today, two lighthouse keepers are regularly flown to the island by helicopter for 28-day shifts to operate a light — even though, like every other lighthouse in Canada, it is automated.
Kelly reasonably suspects that the lack of natural resources in the region have made both sides reluctant to rock the boat by submitting their claims to the International Court of Justice for arbitration, as they have with other disputes. There's simply nothing there worth the risk of losing the case and having to explain to voters why you "gave away" U.S. or Canadian territory. In any case, from the photos on Flickr it looks like the Canadian government has staked a pretty permanent claim to the island, so this one may be de facto settled.
Machias is the only U.S.-Canadian border conflict that involves land, but the sea border is disputed in a few places. Here's Wikipedia's list:
- Strait of Juan de Fuca (Washington / British Columbia) The middle-water line is the boundary, but the governments of both Canada and British Columbia disagree and support two differing boundary definitions that would extend the line into the Pacific Ocean to provide a more definite Exclusive Economic Zone (EEZ) boundary.
- Dixon Entrance (Alaska / British Columbia) is wholly administered by Canada as part of its territorial waters, but the US supports a middle-water line boundary, thereby providing the US more maritime waters. Canada claims that a 1903 treaty demarcation is the international maritime boundary, while the United States holds that the maritime boundary is an equidistant line between the islands that form the Dixon Entrance, extending as far east as the middle-water line with Hecate Strait to the south and Clarence Strait to the north.
- Yukon–Alaska dispute, Beaufort Sea (Alaska / Yukon) Canada supports an extension into the sea of the land boundary between Yukon and Alaska. The US 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 EEZ in the polar region is claimed by Alaska, because the EEZ boundary between Northwest Territories and Yukon follows a straight north-south line into the sea. US claims would create a triangular shaped EEZ for Yukon. This is mainly an Alaska-Yukon dispute.
- 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 last two might get a bit more controversial as resource competition in the rapidly melting Arctic heats up.
Flickr user ducksarefun