Seal Island area Machias Seal Island —and
North Rock (
Maine and
New Brunswick) located in what is known as the "Grey Zone" (about in size), 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 and US Coast Guard, but only the Canadian Coast Guard occupies the lighthouse. The unresolved maritime boundary breaks into two elements: the sovereignty of the island and the location of the maritime boundary, taking into account who is the rightful owner of the island. The disputed area is about in size. was defined in a 1903 arbitration decision on the
Alaska/British Columbia boundary. The court specified the initial boundary point (Point "A") at the northern end of Dixon Entrance and designated Point "B" 72 NM to the east. Canada relies on the "A-B" line as rendering nearly all of Dixon Entrance as its internal waters. 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, The intersecting lines create four separate water areas with differing claim status. The two areas south of the "A-B" line (about and in size) are claimed by both countries. The other two water areas are north of the "A-B" line and are not claimed by either country. The two unclaimed areas are about and in size.) that lies south of the "A-B" Line, surrounded by the sea territory claimed by the U.S. (left) and the boundary currently claimed by the U.S. (right). ==Historical disputes==