This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages)(Learn how and when to remove this template message)
A quadripoint is a point on the Earth that touches the border of four distinct territories. The term has never been in common use—it may not have been used before 1964 when it was possibly invented by the Office of the Geographer of the United States Department of State.[n 1] The word does not appear in the Oxford English Dictionary or Merriam-Webster Online dictionary, but it does appear in the Encyclopædia Britannica, as well as in the World Factbook articles on Botswana, Namibia, Zambia, and Zimbabwe, dating as far back as 1990.
- 1 History
- 2 Four-nation quadripoints
- 3 Quadripoints within and between nations
- 3.1 Argentina
- 3.2 Austria/Germany
- 3.3 Bangladesh/India
- 3.4 Belgium/Netherlands
- 3.5 Canada
- 3.6 Canada/United States of America
- 3.7 Croatia/Hungary/Serbia
- 3.8 Dominican Republic/Haiti
- 3.9 Hungary/Slovakia
- 3.10 Kenya
- 3.11 Lithuania/Poland/Russia
- 3.12 Mexico
- 3.13 Norway/Sweden
- 3.14 Oman/Saudi Arabia/Yemen
- 3.15 Poland/Slovakia
- 3.16 Russia/Kazakhstan
- 3.17 Sweden
- 3.18 United Kingdom
- 3.19 United States
- 3.20 Void or dispute-pendant quadripoints
- 4 Multipoints of greater numerical complexity
- 5 See also
- 6 Notes
- 7 References
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); it combined until 1931 the English shires/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 in Spain.
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). If Moresnet is counted as a country, then national borders came together in this point from five different directions during the existence of Moresnet and the World War I, although never more than four at the same time. 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).
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 (approximately ), it is now generally believed that two separate trijunctions exist perhaps some 100 or 150 meters apart.
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 150 meters between Zambia and Botswana was apparently agreed during various meetings involving heads of state and/or officials from all four states in the 2006–10 period and is clearly shown in the African Development Fund project map (matching the US Department of State Office of the Geographer depiction in Google Earth).
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 actually 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.
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 8 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 quadripoints composed only of primary subdivisions.
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.
On the summit of Sorgschrofen peak, the international boundary touches (or crosses) itself at marker number 110, where two 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).
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 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.
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.
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.[n 2]
Canada/United States of America
Both of the only known international quadripoints in the Western Hemisphere 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.
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 Bacs-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).
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.
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 Fuzer, Hungary, in conjunction with Trstené Pri Hornáde, Slovakia, and Hollohaza, 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-Abauj-Zemplen county of Hungary.
At 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., there is a trinational quadripoint: to the northwest is
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.
On the border of Sweden and Norway, there is a binational quadripoint where two counties of Norway, Nord-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.
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.
At a secondary summit of Pilsko Peak called Gora Pieciu Kopcow, 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 Jelesnia in Zywiec 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).
This quadripoint  is created by Saratov Oblast, Samara Oblast, and Orenburg Oblast from the Russian side of border and West Kazakhstan Region from the Kazakhstani side. The nearest big city is Oral, Kazakhstan.
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.
Due to changes to the borders and numbers of administrative counties in the last century (see administrative counties of England), no true quadripoint remains in the United Kingdom.
But quite apart from the few shire/county quadripoints that have actually existed in England (see History, above), 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 66 ft (20 metres) apart.
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.
A practically identical situation occurs on the boundaries of the Ilemi Triangle, where South Sudan enjoys a void quadripoint, in this case shared with Kenya.
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 7 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 6-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, reclaimed, etc., as national sovereign territory by Argentina, Australia, Chile, France, Great Britain, and New Zealand, if not also Norway). But whatever the ultimate disposition of disputed national sovereignty, the intersection and quadripoint of two undisputedly pristine and two highly 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, naturally and randomly formed, 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 quintipoints 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. Multipoints of greater than quintuple complexity are exceedingly rare.
In Finland near Turku, the borders of seven municipalities merge on the same point: Pöytyä, Aura, Turku, Rusko, Masku, 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, with eight being the largest number; in 2009, Yläne merged back to Pöytyä, bringing the number back to seven.
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 Northern Ireland, ten townlands meet 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 on the summit of Mount Etna. These municipalities are Adrano, Biancavilla, Belpasso, Bronte, Castiglione di Sicilia, Maletto, Nicolosi, Randazzo, Sant'Alfio, 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 (see above section).
- In common American English usage, the much more usual expression for the thing described by the term has been "four corners" (at least until the 1970s and perhaps even still), evidently because the most celebrated quadripoint in the world - which is located in the United States - is named "the Four Corners".
- Akweenda, Sackey (1997). International Law and the Protection of Namibia's Territorial Integrity: Boundaries and Territorial Claims. Martinus Nijhoff. pp. 201–203. ISBN 978-90-411-0412-0.
- Nolan, J. (December 2003). "There are numerous points where three countries meet. Are there any with four?". Geographical. 75 (12): 19. ISSN 0016-741X.
- "Zambia". Encyclopædia Britannica (2010 Online Library ed.). Encyclopædia Britannica. Retrieved 17 November 2010.
- "The World Factbook 1990 Electronic Version". Central Intelligence Agency. 1993. Retrieved 17 November 2010.
- at 238c: DB Warks., 3,4. Books.google.com. Retrieved 2012-05-14.
- Domesday book: Gloucestershire - John Morris - Google Books. Books.google.com. Retrieved 2012-05-14.
- Pickard Trepess. "The Four Shire Stone - Moreton-in-Marsh". Hunimex.com. Retrieved 2012-05-14.
- Boundaries of the United States and the Several States, Franklin K. Van Zandt, 1976. pp. 22ff, 26f, 100-107.
- "Alabama Maps - Historic". Alabamamaps.ua.edu. Retrieved 2012-05-14.
- "Neutral-Moresnet/History". Moresnet.nl. Retrieved 2012-05-14.
- "Guinness Book of Records", 1979 et seq.; see "Shortest Frontier"
- Arnold, Guy (1997). The Resources of the Third World. Taylor & Francis. pp. 252, 319. ISBN 978-1-57958-014-8.
- Anderson, Ewan W. (2003). International Boundaries: A Geopolitical Atlas. Psychology Press. pp. 9, 116, 118. ISBN 978-1-57958-375-0.
- Hinz, Manfred O.; Gatter, Frank Thomas (2006). Global Responsibility – Local Agenda: The Legitimacy of Modern Self-Determination and African Traditional Authority. LIT Verlag Münster. p. 45. ISBN 978-3-8258-6782-9.
- "Zambia and Botswana reach Kazungula bridge deal." Palapye News blog. Retrieved 12 November 2007.
- Darwa, P. Opoku (2011). Kazungula Bridge Project (PDF). African Development Fund. p. Appendix IV. Retrieved 2012-05-04.
- Griffiths, Ieuan Ll (1995). The African Inheritance. Psychology Press. p. 56. ISBN 978-0-415-01092-4.
- Waiting for the Eskimo: An historical and documentary study of the Cooch Behar enclaves of India and Bangladesh (Research paper) by Brendan R Whyte. School of Anthropology, Geography and Environmental Studies, 2002, University of Melbourne, figure 5b on page 479 and figure 4b on page 473, respectively, both instances personally attested by author expert at http://article.gmane.org/gmane.culture.discuss.boundary-point/8342
- "Baarle Nassau and Baarle Hertog". Ontology.buffalo.edu. Retrieved 2012-05-14.
- "quadripoint is shown just below and right of center of map above the word Rethse". Ontology.buffalo.edu. Retrieved 2012-05-14.
- "Nunavut Act". Department of Justice, Canada. Retrieved 28 October 2010.
- "Nunavut Land Claims Agreement" (PDF). Nunavut Tunngavik Incorporated. Retrieved 28 October 2010.
- "Manitoba - Northwest Territories - Nunavut - Saskatchewan Multi-point". The Corner Corner. Retrieved 2010-07-29.
- Canadian Spatial Reference System Online Database, Natural Resources Canada, Geodetic Survey Division. GSD LONG Report for: "MON 157 (name), 674002 (unique number)" (online database requires free registration).
- Boundaries of the United States and the Several States, Van Zandt, supra, p. 14, 21
- "+ theTitle +". Historical-county.newberry.org. Retrieved 2012-05-14.
- "mapserver.mytopo.com". mapserver.mytopo.com. Retrieved 2012-05-14.
- "The Atlas of Canada - Territorial Evolution". Atlas.nrcan.gc.ca. 2009-02-26. Retrieved 2012-05-14.
- Maine Geological Survey
- Private and Special Laws (of Maine) 1895, Chapter 123, dated 5 March 1895, pursuant to Maine State Statutes (Secretary of State's Miscellaneous Papers, IV, p.53, dated 12 April 1873
- "factfinder.census.gov". factfinder.census.gov. Retrieved 2012-05-14.
- downloadable map (English prompts available) Archived 8 July 2010 at the Wayback Machine.
- "(zoomable map)". Kart.statkart.no. Retrieved 2012-05-14.
- (zoomable map) Archived 22 August 2010 at the Wayback Machine.
- "baldwinsmaps.com". baldwinsmaps.com. Retrieved 2012-05-14.
- "Google Translate". Translate.google.com. Retrieved 2012-05-14.
- for tricountry point. Books.google.com. Retrieved 2012-05-14.
- "for official zip file of Yemeni governorate boundaries". Mophp-ye.org. Retrieved 2012-05-14.
- "A real quadripoint?". blanchflower.org.
- Hubbard, Bill, Jr. (2009). American Boundaries: the Nation, the States, the Rectangular Survey. University of Chicago Press. p. 164. ISBN 978-0-226-35591-7. Retrieved 14 November 2010.
- "Four Corners PID AD9256" (text file). NGS Survey Monument Data Sheet. United States National Geodetic Survey. 2003-05-07. Retrieved 2006-12-26.
- "Boundary Study - bs 18 map". Law.fsu.edu. Retrieved 2012-05-14.
- "figure 2, page 62" (PDF). Retrieved 2012-05-14.
- "US NSF - OPP - ANT - The Antarctic Treaty". Nsf.gov. Retrieved 2012-05-14.
- "Archaeology > Sites > Tombs". Peatlands. Northern Ireland Environment and Heritage Service. 2004. Retrieved 31 October 2014.
- "CARN AN TRUAGH, KNOCKLAYD". Northern Ireland Sites and Monuments Records. Northern Ireland Environment Agency. Retrieved 1 November 2014.