Atriple border,tripoint,[citation needed]trijunction,[1]triple point, ortri-border area is ageographical point at which the boundaries of three countries orsubnational entities meet. There are 175 international tripoints as of 2020.[2] Nearly half are situated in rivers, lakes or seas. On dry land, the exact tripoints may be indicated by markers or pillars, and occasionally by larger monuments.
Usually, the more neighbours a country has, the more international tripoints that country has. China with 16 international tripoints and Russia with 11 to 14 lead the list of states by number of international tripoints. Other countries, like Brazil, India, andAlgeria, have several international tripoints. Argentina has four international tripoints. South Africa, Pakistan andNigeria have three international tripoints,Guatemala has two: one with Mexico and Belize, and one with Honduras and El Salvador; whileBangladesh and Mexico have one. Within Europe, landlocked Austria has nine tripoints, among them two withSwitzerland andLiechtenstein.Island countries, such as Japan and Australia, generally have no international tripoints, although some, likeBahrain andSingapore, have tripoints in theirterritorial waters. Countries with only one neighbouring country, such as Portugal orLesotho, also have no international tripoints.Landlocked countries also have international tripoints. Likewise, the United States with two neighbouring countries has no international tripoints; however, it has a number ofstate tripoints as well as one point wherefour states meet. Indonesia has no international tripoints, just like Australia, Japan and the United States. Canada, as well, which has a maritime border with two other countries, has no international tripoints; however, it has five tripoints on land where the boundaries of provinces and territories meet, and one quadripoint wherefour provinces and territories meet. Japan has multiple prefectural tripoints; it also has prefectural quadripoints. In addition to the United States, Canada and Indonesia, Australia also has tripoints where the boundaries of states meet.
Border junctions (or "multiple points" or "multipoints" as they are also sometimes called) are most commonly threefold. There are also a number ofquadripoints, and a handful of fivefold points, as well as unique examples of sixfold, sevenfold, and eightfold points (seequadripoint § Multipoints of greater numerical complexity). The territorial claims of six countries converge at theSouth Pole in a point of elevenfold complexity, though this is an example of pointssubject to dispute.
theTreriksröset of Finland, Norway, and Sweden (the northernmost international tripoint in the world; the exact point is in a lake, but a marker is built on that point)
theVaalserberg of the Netherlands, Germany, and Belgium
the "Dreiländereck" of Germany, France, and Switzerland (the exact point is in the river and the marker is not on the exact point)
theSchengen tripoint of Germany, France, and Luxembourg (where theSchengen Agreement was signed on board a boat, since the tripoint is in the river)
the summit ofSia Kangri (nearIndira Col) is the tripoint where territories administered by India, Pakistan, and China meet
Bratislava is the only capital city in the world which is located at a tripoint:Slovakia,Hungary, andAustria. The city's administrative area extends to the tripoint, but the point lies outside of urban Bratislava itself.
Marker at the Tarvagan Dakh Mongolia/Russia/China tripoint in 2020, from the Mongolian side
While the exact line of an international border is normally fixed by a bilateral treaty, the position of the tripoints may need to be settled by a trilateral agreement. For example, China, Russia, and Mongolia have set the position of the two relevant tripoints (the junction points of theChina–Russia border, theMongolia–Russia border, and theChina–Mongolia border) by the trilateral agreement signed inUlaanbaatar on January 27, 1994. The agreement specified that a marker was to be erected at the eastern tripoint, called Tarvagan Dakh (Tarbagan Dakha), but that no marker would be erected at the western tripoint (which was defined as the peak of the mountain Tavan-Bogdo-Ula (Kuitunshan, Tavan Bogd Uul).[5]