Tripoint

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A triple border, tripoint,^{[citation needed]} trijunction,^[1] triple point, or tri-border area is a geographical point at which the boundaries of three countries or subnational 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, and Algeria, have several international tripoints. Argentina has four international tripoints. South Africa, Pakistan and Nigeria have three international tripoints while Bangladesh and Mexico have only one. Within Europe, landlocked Austria has nine tripoints, among them two with Switzerland and Liechtenstein. Island countries, such as Japan and Australia, have no international tripoints (some, like Bahrain and Singapore, have tripoints in the territorial waters), and the same goes for countries with their only neighbour country, such as Portugal or Lesotho. Landlocked countries also have international tripoints. Likewise, the United States with two neighbouring countries has no international tripoints; however, it has a number of state tripoints as well as one point where four 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 where four 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 of quadripoints, and a handful of fivefold points, as well as probably unique examples of sixfold, sevenfold, and eightfold points (see quadripoint § Multipoints of greater numerical complexity). The territorial claims of six countries converge at the south pole in a point of elevenfold complexity, though this is an example of points subject to dispute.