In geography, a quadripoint is a point on the Earth that touches four distinct regions. Such points are often called "four corners", from the corners of the four regions meeting there.
At present there are no generally recognized quadripoints involving four different countries, although a claim is often made that one exists at between Namibia
at the thalweg confluence
of the Zambezi River
with the Chobe River
. The various boundary definitions involved are subject to differing and disputed interpretations; only one combination of interpretations and river conditions might have produced a quadripoint, but that combination never obtains in reality.
If the Kazungula case above is not accepted as a quadripoint, it is the place where tricountry points are closest together, as the distance between the tripoints is believed by the most careful authorities to be on the order of 100 meters.
Where two tripoints occur very close to each other, they can look like a quadripoint on a map of insufficient resolution. For example, the Kazakhstan/Russia/People's Republic of China tripoint at is only 39 km from Tavan Bogd Uul, a Russia/Mongolia/People's Republic of China tripoint. It may look like a quadripoint on some maps, but at more detailed resolution, it is clear that Kazakhstan and Mongolia never touch.
An even closer example of this is between the tripoints of Armenia/Turkey/Nakhichevan, Azerbaijan and Iran/Turkey/Nakhichevan, Azerbaijan, which are about 9 km from each other at .
Although four countries border Lake Chad, there is no quadripoint of Chad, Niger, Nigeria, and Cameroon within the lake. The two tripoints are about 86 km apart.
Similarly, the Gulf of Aqaba in the Red Sea borders four countries, but does not contain a quadripoint of Jordan, Saudi Arabia, Egypt, and Israel.
Some political maps of the South Pacific enclose many island nations within straight lines drawn along parallels of latitude or meridians of longitude, often with a maritime quadripoint indicated for Solomon Islands, Tuvalu, Kiribati, and Nauru. This is not a meaningful quadripoint, as the lines are simply cartographic conveniences to indicate which country the islands within it belong to, and are thus merely allocational lines rather than actual international boundaries of territorial waters or Exclusive Economic Zones.
Previously existing would-be four-country points
Between 1830 and 1920 there was a quadripoint at the convergence of Belgium
, the Netherlands
, and Moresnet
This point has often been called a quadricountry point, though Moresnet was never truly a country but rather only a neutral territory or condominium of the Netherlands and Prussia (originally), and of Belgium and Germany (ultimately).
From 1922 to 1991 there was a de facto quadripoint between Iraq, Kuwait, Kingdom of Nejd/Saudi Arabia and the Saudi-Iraqi neutral zone, although precise boundaries were never specified by the three sovereign states.
Fewer than four countries
There are quadripoints where four border lines touch each other at one point, but involving fewer than four countries. This occurs with a practical exclave
which touches the main territory (or another exclave) at a single point. The Belgian enclaves H1 and H2 in Baarle-Hertog
touch each other at one such point, while the Netherlands also crosses it.
Similarly, the Austrian town of Jungholz lies totally within Germany except that it borders Austria at one single point.
Cooch Behar in India is linked with Bangladesh by at least one such point (and very possibly a second).
A secondary quadripoint (or "quadrisecondary point") is the meeting of four political subdivisions (for example, provinces, states, or cantons). The four subdivisions may all belong to one country, or they may involve two or three different countries.
By analogy, one could speak of tertiary quadripoints ("quadritertiary points") where, for example, four different counties meet at one point, and quaternary quadripoints ("quadriquaternary points") where four municipalities meet, etc. However, these lesser categories would not have been considered as interesting as primary or "world class" quadripoints, if indeed any such quadricountry points had ever actually existed. For example, many of the counties of Nebraska or the towns of Maine are demarcated as squares in a grid.
At , there is a trinational secondary quadripoint: to the northwest is Russia
(specifically the Russian exclave Kaliningrad Oblast
); to the northeast Lithuania
; and to the southwest and southeast two Voivodships (provinces) of Poland
: Warmian-Masurian Voivodship
and Podlaskie Voivodeship
The quadripoint exists thanks to the way the border between Poland and Russian SFSR
was defined in 1945 by the Potsdam Agreement
At or around , there appears to be another trinational secondary quadripoint: to the north is Saudi Arabia, to the southeast is Oman, and to the southwest two Governorates of Yemen: Hadhramaut Governorate to the westsouthwest and Al Mahrah Governorate to the southsouthwest.
The three German states Bavaria
, and Thuringia
(the two tripoints are about 20 km apart), do not form a quadripoint with the Czech Republic
; nevertheless it is frequently commented on.
A similar seeming quadripoint exists near Biaufond at between the Swiss cantons of Jura, Neuchâtel, and Berne on the one hand, and the French département Doubs on the other hand. In this case, the two tripoints are separated by only about 250 m/830 ft.
On the border of Sweden and Norway, at , there appears to be a binational secondary quadripoint where two Counties of Norway, Nord-Trøndelag and Nordland, meet two Counties of Sweden, Västerbotten County and Jämtland County.
Another binational secondary quadripoint appears to exist on the border of Argentina and Uruguay where the Argentinian provinces of Corrientes and Entre Rios also very probably meet the Uruguayan departments of Artigas and Salto.
provinces of La Pampa
, Río Negro
form a quadripoint at , though Rio Negro has disputed this since a 1966 resurvey cast the exact boundary convergence into some doubt.
The Four Corners is the only point in the United States of America where four states meet: Colorado, Utah, New Mexico, and Arizona meet at right angles.
There has been an analogous Four Corners in Canada at since the creation of Nunavut in 1999; it meets Saskatchewan at a point, with Manitoba and the Northwest Territories at the other corners. Before 1999 this was a tertiary quadripoint, with Manitoba, Saskatchewan, and the then existing Northwest Territories districts of Mackenzie and Keewatin.
Four provinces of the Philippines meet at a point on Mindanao island, probably at one of the three peaks of Mount Apo: Bukidnon, Davao del Norte, Davao del Sur, and Cotabato.
There are two quadripoints in Switzerland where three cantons meet. At each, a practical exclave of one canton touches its parent, while two other cantons touch each other. One is near , where the municipality of Roggenburg is cut off from its parent Basel-Country by Jura to the south and an exclave of Solothurn to the north. The other is near where Jura again touches Solothurn, cutting off the municipality of Schelten from its parent canton of Bern.
Other countries that enjoy very probable (or positively confirmed) secondary quadripoints are Andorra, Bulgaria, the Dominican Republic, Gabon, India, Jamaica, Liechtenstein, Mauritania, Oman, Sudan, Uganda, and Vietnam.
An analysis of county quadripoints in the United Kingdom is complicated by the fact that the borders and numbers of administrative counties have changed several times in the last century (see Administrative counties of England). No true quadripoints remain in the United Kingdom.
Until the late nineteenth century, one quadripoint did exist; near Evenlode in Gloucestershire, is "Four Shire Stone", formerly at an intersection of Gloucestershire, Oxfordshire, Warwickshire, and a detached fragment of Worcestershire. However, the fragment has been reassigned, leaving only a tripoint around ten miles (16 km) from modern Worcestershire.
In addition there are a few near misses. The most famous lies south west of Stamford – where Rutland, Lincolnshire, Cambridgeshire and Northamptonshire seem to meet at a point. However, the location actually consists of two tripoints around 20 metres apart.
In addition near East Grinstead, the East Sussex-West Sussex-Surrey and East Sussex-Surrey-Kent tripoints are only a mile apart. Similarly the Staffordshire-Warwickshire-Leicestershire and Warwickshire-Leicestershire-Derbyshire tripoints are again around a mile apart. And until 1965, the two tripoints formed by Gloucestershire, Oxfordshire, Wiltshire and Berkshire near Lechlade came very close to one another. ().
Five or more regions
At subnational level, one can find even more than four divisions converging at a point.
- Five counties in Florida meet within Lake Okeechobee: Okeechobee, Martin, Palm Beach, Hendry, and Glades.
- In the Philippines:
- Municipalities of Tagkawayan, Quezon Province; Labo, San Vicente and San Lorezo Ruiz, Camarines Norte; and Del Gallego, Camarines Sur
- Cities of Cadiz, Sagay, Silay and Talisay, and municipality of Calatrava, Negros Occidental
- Municipalities of Carmen, Batuan, Bilar, Dimiao, and Valencia, Bohol
- Municipalities of San Miguel, Ubay, Alicia, Dagohoy and Pilar, Bohol
- Malaybalay City, Sumilao, Baungon, Talakag and Lantapan, Bukidnon
- Municipalities of Carmen, Aleosan, Pikit and Kabacan, Cotabato; and Pagagawan, Maguindanao
- Municipalities of Tibiao and Barbaza, Antique; Madalag and Libacao (a close call?), Aklan; and Jamindan, Capiz
- Municipalities of Basey and Marabut, Samar; and Balangkayan, Llorente, Balangiga and Lawaan, Eastern Samar, Philippines
Cases of Tertiary octopoints:
This article was originally translated from the Dutch-language wiki article Vierlandenpunt
, as of 2006-06-20
, with the assistance of SystranBox online machine translation