Quadripoint - Quadripoints Within and Between Nations

Quadripoints Within and Between Nations

Quadripoints can exist at the meeting of political subdivisions of any type(s) or level(s). The most common are in the United States and Canada, where the grid-based Public Land Survey System (PLSS) and Dominion Land Surveys (DLS), respectively, resulted in a large number of quadripoints at the corners of survey units such as DLS townships, PLSS townships, sections, and various other gridded subdivisions. The borders of U.S. counties and towns are often defined by survey townships. There are dozens of quadripoints between U.S. counties, hundreds between U.S. municipalities, and indeed thousands (of usually bilateral ones) on the edges of checkerboard-patterned Indian reservations and other federally reserved territories. But of all the quadripoints that exist, the most noted are about 10 international instances, and about 10 others of primary national subdivisions (such as provinces or states).

Among the international quadripoints (examples below) a few general types can be distinguished. In the absence of four-country points, three-country quadripoints are perhaps most significant. These combine two divisions of one country with (one each of) two other countries. But there also exist merely binational quadripoints—of several varieties. Some of these combine two subdivisions of two countries, others three subdivisions of one country with (one of) another; while still others occur at points where international boundaries appear to touch or cross themselves—with or without subdivision—or where an international boundary appears to bifurcate around disputed territories.

Also below, by country, some quadripoints composed only of primary subdivisions.