
Quadripoint

A quadripoint is a point on Earth where four distinct territories meet. The territories can be of different types, such as national and provincial. Several examples exist throughout the world that use other names. In North America, several such places are more commonly known as Four Corners.
Usage.
The word "quadripoint" does not appear in the "Oxford English Dictionary" or "Merriam-Webster Online", though it has been used since 1964 by the Office of the Geographer of the United States Department of State. and appears in the "Encyclopædia Britannica", as well as in the "World Factbook" articles on Botswana, Namibia, Zambia, and Zimbabwe, dating as far back as 1990.
History.
An early instance of four political divisions meeting at a point is in England (attested in the Domesday Book, 1086, and mentioned since 969 if not 772); until 1931, it was the meeting point of the English counties of Gloucester, Oxford, Warwick, and Worcester.
The earliest known quadripoint involving modern nation-states existed from 1817 to 1821 where the present Alabama–Mississippi state line crossed the 31st parallel border between Spain and the United States. During that period, the part of West Florida between the Pearl and Perdido rivers (which Spain still owned but the United States forcibly occupied and annexed in 1810 after belatedly claiming it as part of the Louisiana Territory purchased from France in 1803) was subdivided and allocated partly to the State of Mississippi and partly to the Territory (and later State) of Alabama. There resulted, at the intersection of demarcated boundaries, an international quadripoint of four territories, which in the United States were named (clockwise) Baldwin and Mobile counties of Alabama and Jackson and Greene counties of Mississippi, though Mobile and Jackson Counties were actually still Spanish.
Between 1839 and 1920 there was a quadripoint at the convergence of Belgium, Prussia/Germany, the Netherlands, and Moresnet at Vaalserberg. 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). Subsequent political changes have restored its quadripartition along municipal lines (Kelmis, Plombieres within Belgium) since 1976 (though it has also enjoyed fivefold partition along municipal lines at times).
Four-nation quadripoints.
Botswana–Namibia-Zambia-Zimbabwe.
While some older sources claimed that a quadripoint existed in Africa, where the borders of Namibia, Botswana, Zambia, and Zimbabwe come together at the confluence of the Cuando (also called Chobe) and Zambezi rivers, it is now widely believed that instead, two separate tripoints exist about apart.
There have been a few international incidents revolving round this particular quadripoint, or near-quadripoint. In 1970, South Africa (which at the time occupied Namibia) informed Botswana that there was no common border between Botswana and Zambia, claiming that a quadripoint existed. As a result, South Africa claimed, the Kazungula Ferry, which links Botswana and Zambia at the quadripoint, was illegal. Botswana firmly rejected both claims. There was a confrontation and shots were fired at the ferry; some years later, the Rhodesian Army attacked and sank the ferry, maintaining that it was serving military purposes. Ian Brownlie, who studied the case, wrote in 1979 that the possibility of a quadripoint could not be definitively ruled out at that time.
In August 2007 the governments of Zambia and Botswana announced a deal to construct a bridge at the site to replace a ferry. The existence of a short boundary of about between Zambia and Botswana was apparently agreed during various meetings involving heads of state or officials from all four states in the 2006–10 period, and is clearly shown in the African Development Fund project map. This matches the data kept by the Office of the Geographer under the US Department of State, as depicted in Google Earth.
Cameroon–Chad–Nigeria–United Kingdom.
However, a true four-country point did formerly exist in Africa (excluding Kazungula) – the only known quadricountry borderpoint (not involving condominial territories) – for a period of eight months during 1960 and 1961, in southern Lake Chad, at the location of the present Cameroon–Chad–Nigeria tripoint. Upon the 1 October 1960 independence of Nigeria, that borderpoint became common to the latter three countries and the territory of Northern Cameroons, which was still governed under United Nations mandate by the United Kingdom, until it was finally integrated into Nigeria on 1 June 1961. This particular geographical multipoint, though notional since 1908, if not 1891, and definitely fixed and fully agreed since 1931, remains undemarcated to this day.
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 a few dozen that are situated on international borders, and about a dozen others involve 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, are some subnational quadripoints composed of subdivisions.
Algeria–Mali–Mauritania.
Two districts of Adrar Province, Algeria—namely Bordj Badji Mokhtar and Reggane—meet the Tombouctou Cercle of Tombouctou Region, Mali, and the Bir Mogrein Department of Tiris Zemmour Region, Mauritania.
Andorra.
In northern Andorra, the four "parròquies" 
or parishes of Canillo, Encamp, La Massana, and Ordino, meet at a quadripoint.
Argentina.
The Argentine provinces of La Pampa, Río Negro, Mendoza, and Neuquén may meet at . Río Negro has disputed this since a 1966 resurvey cast the exact boundary convergence into some doubt.
Austria–Germany.
On the summit of Sorgschrofen peak, the international boundary touches (or crosses) itself at marker number 110, where one Austrian (Tyrolean: Reutte) and two German (Bavarian: Oberallgäu, Ostallgäu) municipalities meet at a quadripoint established politically in 1844, cadastrally 1342 or earlier: (in clockwise order) Jungholz (Austria), Pfronten (Germany), Schattwald (Austria), and Bad Hindelang (Germany).
Bangladesh–India.
When almost all of the India–Bangladesh enclaves were extinguished by the Land Boundary Agreement between the two states, effective after 31 July 2015, which exchanged all first-order exclaves, the following quadripoint(s) was(were) thus also extinguished. The international boundary touched (or crossed) itself at one (or possibly two) locations shared by India (West Bengal state, Cooch Behar district) and Bangladesh (Rangpur Division, Lalmonirhat District). A confirmed instance occurred in Mathabhanga subdivision and a less definite one in Mekhliganj subdivision (of Cooch Behar), involving the Bara Saradubi enclave of Hatibandha thana and the Jote Nijjama enclave of Patgram thana (of Lalmonirhat), respectively. Additional political subdivision did not appear to result in either case. Its (or their) international stature had been intermittent since Mughal times and was a result of the Radcliffe Award of 1947.
Belgium–Netherlands.
The international boundary touches (or crosses) itself, without imparting political subdivision, within the commingled municipalities of Baarle-Nassau (North Brabant, Netherlands) and Baarle-Hertog (Antwerp, Belgium). The peculiar situation, which occurs at Baarle but once (at the touchpoint of Belgian enclaves H1 and H2), has existed at least cadastrally since about 1198, but its current international distinction dates only from 1830.
Benin–Burkina Faso.
Since 2009, Benin and Burkina Faso have jointly administered a neutral zone called Kourou or Koalou that lies tangent to their boundary junction with Togo, producing the sort of tricountry quadripoint that adjoined the defunct Moresnet neutral zone illustrated above.
Canada.
The creation of the Canadian territory of Nunavut might have resulted in the creation of a quadripoint between the provinces of Saskatchewan and Manitoba and the territories of Nunavut and Northwest Territories (NWT). Nunavut was officially separated from the Northwest Territories in 1999, though the boundaries had been defined in 1993 by the Nunavut Act and the Nunavut Land Claims Agreement. Both documents define Nunavut's boundary as including the "intersection of 60°00'N latitude with 102°00'W longitude, being the intersection of the Manitoba, Northwest Territories and Saskatchewan borders". However, the northernmost point of the Manitoba–Saskatchewan border as surveyed is slightly off from 60° north 102° west, therefore the laws are not perfectly clear about whether the Nunavut–NWT boundary, which has not been surveyed, is to meet the others in a quadripoint or not.
Canada–United States.
Both of the only known international quadripoints in the Americas occur on the Canada–United States border along remote mountain crests. One, which joins the Canadian provinces of Alberta (Improvement District Number 4) and British Columbia (Regional District of East Kootenay) with the Montana counties of Flathead and Glacier where the 49th parallel crosses the Continental Divide also unites an international peace park comprising national parks of both countries (Waterton Lakes and Glacier, respectively). It has been a politically important and precisely stipulated international boundary point since 1818; has been monumented since 1876 (now by a hollow metallic obeliskoid marker numbered 272); and has maintained a quadripartite status since 1893.
The other of the pair occurs in the international boundary sector known as the Highlands, on the ridge separating the Gulf of Saint Lawrence watershed from the Gulf of Maine watershed, where three minor civil divisions of the state of Maine—namely Dennistown Plantation, Forsyth, and Sandy Bay Townships, all in Somerset County—meet Le Granit Regional County Municipality of the province of Quebec. This quadripoint, which was legally delimited in 1873 and validated in 1895, is marked (like all the corners of the minor civil divisions of Maine) by a brightly painted 8-foot wooden pole.
Colombia.
There is a subnational quadripoint in Colombia at approximate coordinates , at the confluence of the Upía and Guavio rivers, where the borders of the Boyacá, Casanare, Meta, and Cundinamarca departments come together.
Croatia.
The summit of Risnjak mountain in Primorje-Gorski Kotar County is a meeting point of five municipalities: Čabar, Delnice, Lokve, Bakar and Čavle, making it a quintipoint.
The municipalities of Vrbanja, Drenovci, Bošnjaci and Nijemci in Vukovar-Srijem County meet at a quadripoint just south of the A3 motorway, near Spačva.
The municipalities of Magadenovac, Marijanci, Valpovo and Koška in Osijek-Baranja County meet at a quadripoint on the river Breznica.
The municipalities of Krapina, Mihovljan, Bedekovčina and Sveti Križ Začretje in Krapina-Zagorje County meet at a quadripoint just north of the village of Komor Začretski.
The municipalities of Čakovec, Sveti Juraj na Bregu, Selnica and Mursko Središće in Međimurje County share a quadripoint north of the village of Žiškovec.
Croatia–Hungary–Serbia.
At a delimitation point determined partly following World War I and partly following World War II, and indirectly monumented by international pillars 415 and 420 on respective riverbanks, there is on the thalweg (center of downstream navigation channel) of the Danube a trinational quadripoint, where the Hungarian counties of Baranya and Bács-Kiskun meet the Croatian county of Osječko-Baranjska and the Serbian (Vojvodina) District of West Bačka (although Croatia continues to claim its former Yugoslav cadastral territory east of the Danube, leaving the quadripoint technically unsettled).
Dominican Republic–Haiti.
On the border of the Dominican Republic and Haiti, there is a binational quadripoint where two departments of Haiti, Centre and Ouest, meet two provinces of the Dominican Republic, Elias Pina and Independencia, at the ridgeline of a feature that is called the Sierra de Neiba in the Dominican Republic and the Chaine du Trou de l'Eau in Haiti, and which a 19th-century communal boundary followed before the intersecting 20th-century international boundary was created. As well, some to the east along the same ridgeline, the same two Dominican provinces produce a subnational quadripoint where they meet two other Dominican provinces, Baoruco and San Juan.
Gabon.
Four provinces (the primary subdivision) of Gabon, namely Moyen-Ogooué, Ngounie, Ogooué-Ivindo, and Ogooué-Lolo, meet at a quadripoint in La Lopé National Park (at roughly ). Moreover at least one instance of four departments (the secondary subdivision), namely Haut-Ntem, Ivindo, Okano, and Woleu, also meet at a quadripoint.
Hungary–Slovakia.
The border between Hungary and Slovakia most probably leads the world in international quadrimunicipal points with no fewer than five, but this border is also unique for hosting the only known pair of linked quadrimunicipal points in the world—which are shared in common by the towns of Skaros, Slovakia, and Füzér, Hungary, in conjunction with Trstené Pri Hornáde, Slovakia, and Hollóháza, Hungary, in one case, and Slaska Huta, Slovakia, and Pusztafalu, Hungary, in the other. All these towns are in either the Košice Okolie district of the Košice region of Slovakia or the Borsod-Abaúj-Zemplén county of Hungary.
Iraq–Saudi Arabia.
From 1922 - 1981 Iraq and Saudi Arabia jointly administered a large neutral zone immediately west Kuwait, forming a distinctive diamond shape which create a quadripoint at the Kuwait border.
Ireland.
Between the traditional counties of Ireland there are many tripoints but no true quadripoints. The three closest quartets can all be found along different sections of the Meath county boundary. At the northern apex of Meath, the counties of Cavan, Louth, Meath and Monaghan are all less than five kilometres separate along the Meath-Monaghan border near the towns of Ardee, Co. Louth and Kingscourt, Co. Cavan. Similarly in the northwest corner of Meath, the boundaries of Cavan, Longford, Meath and Westmeath lie within five kilometres of the Cavan-Westmeath border running through Lough Sheelin. Meanwhile, in the southwest corner of Meath, the limits of Kildare, Meath, Offaly and Westmeath are all less than ten kilometres separate at the Meath-Offaly border between the village of Milltownpass, Co. Westmeath and Cadamstown, Co. Kildare on the outskirts of Edenderry. Elsewhere in Ireland, the Munster counties of Cork, Limerick, Tipperary and Waterford are all little more than ten kilometres separate along the Cork-Tipperary border east of Mitchelstown, Co. Cork and near Ballyporeen, Co. Tipperary. These near-quadripoints are of particular interest to walkers, runners and cyclists who may wish to visit four or more counties in the shortest possible distance.
Jamaica.
Four parishes of Jamaica, namely Clarendon, Manchester, Saint Ann, and Trelawny, meet at a quadripoint.
Kazakhstan–Russia.
A quadripoint is created by Saratov Oblast, Samara Oblast, and Orenburg Oblast from the Russian side of the border and West Kazakhstan Region from the Kazakhstani side.
Lithuania–Poland–Russia.
At , there is a trinational quadripoint: to the northwest is Russia (specifically the Russian exclave Kaliningrad Oblast); to the northeast Lithuania; and to the southwest and southeast two voivodeships (provinces) of Poland: Warmian-Masurian Voivodeship 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. The new border between Poland and the USSR bisected Germany's former province of East Prussia; the northern part became Kaliningrad Oblast, and most of the southern part is now Warmia-Masuria.
Mauritania.
Four regions of Mauritania, namely Adrar, Brakna, Tagant, and Trarza, meet at a quadripoint formed by an intersection of non-cardinally oriented geodesic lines that define their borders.
Mexico.
In Mexico there is one precise quadripoint at . The "Mojonera de los cuatro estados" ("Four State Boundary Stone") was built to mark the point where Coahuila, Nuevo Leon, San Luis Potosi, and Zacatecas states effectively meet.
Norway–Sweden.
On the border of Sweden and Norway, there is a binational quadripoint where two counties of Norway, Trøndelag and Nordland, meet two counties of Sweden, Västerbotten and Jämtland, at international boundary marker number 204 (). Though the marker dates from 1760, the point became a quadripoint in the 19th century and became international upon the dissolution of Sweden and Norway in 1905.
Oman–Saudi Arabia–Yemen.
Amid the Empty Quarter of Arabia—as trilaterally agreed and monumented in 2006 precisely at the intersection of the 19th parallel and 52nd meridian (datum uncertain)—Oman (governorate of Dhofar) and Saudi Arabia (emirate of Ash Sharqiyah) meet Yemen (and its governorates of Al Mahrah and Hadramawt) in a tricountry quadripoint.
Poland–Slovakia.
At a secondary summit of Pilsko Peak called Góra Pięciu Kopców, where there is situated a prominent turnpoint on the border of Poland and Slovakia that is evidently demarcated by a primary border marker numbered III/109, there lies a binational quadripoint at which the rural gmina or municipality of Jeleśnia in Żywiec County of the Silesian Voivodeship of Poland apparently meets three municipalities of Námestovo District of Žilina Region of Slovakia called, respectively, Mutne, Oravské Veselé, and Námestovo (although it is unclear if the last-mentioned is an outlier of the eponymous district seat or just an unorganized territory of the Námestovo District itself).
Suriname.
In the Coppename River Suriname enjoys a quadripoint of the districts of Coronie, Para, Saramacca, and Sipaliwini.
Sweden.
In 2007, the municipality of Heby was transferred to Uppsala County, causing Heby of Uppsala County to border the counties of Västmanland, Dalarna, and Gävleborg at the junction of Dalälven and Norrsundet in Färnebofjärden. This was previously a county-level tripoint when Heby was a part of Västmanland. The point forms approximate right angles, and is located on an island in the Dalälven river at .
United Kingdom.
Due to changes to the borders and numbers of administrative counties in the last century, no true county quadripoint remains in the United Kingdom.
But quite apart from the few shire/county quadripoints that have actually existed in England, mistaken claims of an extant one are sometimes made about a place near Stamford where Rutland, Lincolnshire, Cambridgeshire, and Northamptonshire seem to meet at a point (). However, the location actually consists of two tripoints around apart.
The village of Four Marks in Hampshire is so named, because historically four adjoining tithings (or parishes) of Medstead, Ropley, Faringdon, and Chawton met there in a quadripoint.
United States.
The Four Corners Monument is the only point in the United States where four states meet: Colorado, Utah, New Mexico, and Arizona meet at right angles. The United States first acquired the area now called Four Corners from Mexico after the Mexican–American War in 1848. In 1863 Congress created Arizona Territory from the western part of New Mexico Territory. The boundary was defined as a line running due south from the southwest corner of Colorado Territory, which had been created in 1861. By defining one boundary as starting at the corner of another Congress ensured the eventual creation of four states meeting at a point, regardless of the inevitable errors of boundary surveying. The monument is centered at .
Void or dispute-pendant quadripoints.
A pair of conflicting territorial claims can give rise to a void or dispute-pendant quadripoint: of the territory in dispute and the adjacent undisputed territories of the claimants with a fourth territory (or void area) claimed by neither of them.
An international case of such a quadripoint on dry land can be inferred, if not actually found, in a remote area of the Nubian Desert involving both the Hala'ib Triangle and Bir Tawil (about midway between the River Nile and the Red Sea) where the long established but undemarcated international border along the 22nd parallel, as claimed by Egypt, is intersected by a similarly well established administrative boundary preferred and claimed by Sudan as the true international border.
Another occurrence—actually a chain of three such quadripoints linked to two separate unclaimed areas—is inferred where the southern end of the Alaska sector of the Canada–US border aberrates into two crisscrossing versions or claim lines. These conflicting lines produce, besides two areas of overlapping claims, two small triangles of void or virtual high seas—one having two pendant quadripoints and the other a third, all identifiable at fairly precise geocoordinates—as they lurch through the narrows of Dixon Entrance toward their still indefinite boundary termination in the true high seas of the Pacific.
Yet another quadripoint of this type exists on the disputed Thai–Cambodian boundary a short distance northeast of Preah Vihear Temple.
And finally, combining the only other two (of the seven known) unclaimed or void areas on Earth, is a seventh dispute-pendant quadripoint, at the South Pole. Being at once a simple bilateral quadripoint and a far more complicated intersection of claim limits (an elevenfold six-country point), the South Pole example combines two parcels of virgin unclaimed land with two parcels of Antarctic Treaty regulated territory (which have been variously claimed, disputed, recognized, ignored, disowned, and reclaimed as national sovereign territory by Argentina, Australia, Chile, France, the United Kingdom, and New Zealand, if not also Norway). But whatever the ultimate disposition of disputed national sovereignty, the intersection and quadripoint of two pristine and disputable territories endures. The void areas meet the polar quadripoint between the 90th and 150th meridian west longitude (Marie Byrd Land) and, again, between the 20th meridian west and 45th meridian east (this latter sector, of indefinite extent, owing to the Norwegian exclusion of the South Pole from Queen Maud Land), while sovereign or treaty-regulated areas converge at the polar quadripoint in the two intervals between the void areas.
Multipoints of greater numerical complexity.
Quadripoints are exceptional and rare because borders and territories do not normally meet in groups of more than three (viz., at tripoints). Correspondingly and proportionally rarer are points of more than fourfold constituency. Perhaps a dozen quinquepoints of various levels of geopolitical subdivisions are scattered around the world; for example five counties of Florida, United States, meet in the middle of Lake Okeechobee, and the five parishes of Nevis, one of the two islands that make up St Kitts and Nevis, meet on Nevis Peak in the centre of the island. Multipoints of greater than quintuple complexity are exceedingly rare.
In Finland near Turku, the borders of six municipalities merge on the same sexapoint: Pöytyä, Aura, Turku, Rusko, Nousiainen, and Mynämäki meet on the Kuhankuono border marker in Kurjenrahka National Park. The oldest recorded mention of the point dates to 1381, and the number and identity of municipalities participating has varied.
Eight communities of three districts of Papua-New Guinea meet at a single point, at the summit of Mt. Taraka on Bougainville Island, in North Solomons province. The communities are Lato, Motuna-Huyono and Koraru (within Boku district); Makis, Konnou and Wisai (in Buin district); and Bakong and Bakada (in Kieta district). The resulting octopoint is thus a higher-level tripoint as well.
In the Philippines, an octopoint exists at the summit of Mayon Volcano, where eight municipalities in Albay meet. In the nearby province of Camarines Sur, the peak of Mount Isarog is a hexapoint.
In Northern Ireland, ten townlands meet at a decempoint at the summit of Knocklayd (clearly shown by Ordnance Survey mapping at point 311518 436392). The townlands are, clockwise from north, Broom-More, Tavnaghboy, Kilrobert, Clare Mountain, Aghaleck, Corvally, Essan, Cleggan, Stroan, and Tullaghore.
Similarly in Italy, the borders of ten municipalities meet at another decempoint, at the summit of Mount Etna. These municipalities are Adrano, Biancavilla, Belpasso, Bronte, Castiglione di Sicilia, Maletto, Nicolosi, Randazzo, Sant'Alfio, and Zafferana Etnea. The territory of Bronte touches the summit of Mount Etna from two sides, making this decimunicipal point one of elevenfold complexity, and thus evidently the most complicated geopolitical multipoint anywhere, other than the South Pole discussed at #Void or dispute-pendant quadripoints above.