At the end of the Tsawwassen peninsula is the town of Point Roberts. The only land route leading to this part of the United States was entirely within Canada.
After the war in 1812, the Treaty of 1818 between Great Britain and the United States posed a difficult problem: demarcating the border between Canada and America. In order to minimize controversy and ambiguity when drawing borders based on a natural dividing line, the two countries agreed to a simpler solution: the 49th parallel.
Although simple, this solution is not easy, because it also raises a lot of problems such as the fact that Vancouver Island is divided in two by an imaginary line. It is debated whether to rely on latitude to split the island in half, or let Canada own all of that territory under the Oregon boundary dispute that lasted throughout the 19th century.
In 1846, the 11th US President James K. Polk proposed that Vancouver should be an island belonging to two countries. Of course, the British are opposed to this idea. In the end, the two sides agreed to let Canada own all of Vancouver Island, and leave the San Juan Islands to the US.
It seems that the border problem has been completely solved, in fact not really. Because of the limited knowledge of geography, neither the Americans nor the British at that time paid attention to the Tsawwassen peninsula. The peninsula was an unexplored place at the time, but when it was known it was too late.
Today, the end of the Tsawwassen peninsula is an American town called Point Roberts. The only land road leading to this is entirely within Canada. This town of more than 1,300 people has a hospital, police station, fire station, library, marina and an elementary school.