Machais Seal Island, Maine

The eastern end of the international boundary between the USA and Canada begins with uncertainty, ten miles off the coast, at Machais Seal Island, a 20-acre treeless outcrop which is still claimed by both nations. The British built a lighthouse on the island in 1832, claiming it for Nova Scotia, and the Canadian government, which has since automated all the other lighthouses along their coast, keeps this one staffed for the purpose of making a claim for continuous occupation and sovereignty. The USA also claims the island, and a commercial tour operator brings birdwatchers to the island from the coast of Maine. For the moment, without any resources other than the lobsters in the fishery grey zone around the island, there has not been any reason to fight over the island. Both nations think of it as theirs. Though there are a few other remaining boundary disputes between the USA and Canada concerning coastal waters and their respective Exclusive Economic Zones on the west coast, this is the only remaining unsettled boundary dispute over dry land. The island, at the gateway to the longest international boundary in the world, is a borderless space.