Durand Line :
Between Pakistan and Afghanistan, demarcated by Sir Mortimer Durand in 1896.
Hindenberg Line :
The line to which the Germans retreated in 1917 during the First World War, defines the boundary between Germany and Poland.
Line of Control :
It divides Kashmir between India and Pakistan.
Maginot Line :
Boundary between France and Germany.
Mannerheim Line :
Drawn by General Mannerheim; fortification on the Russia an Finland border.
McMahon Line :
The boundary between India and China as demarcated by Sir Henry McMahon in 1914. China does not recognise this line.
Oder Niesse Line :
Boundary between Germany and Poland.
Radcliffe Line :
Drawn by Sir Cyril Radcliffe in 1947 as demarcation between India and Pakistan.
Seigfrid Line :
Line of fortification drawn by Germany on its border with France.
17th Parallel :
The line which defined the boundary between North Vietnam and South Vietnam before the two were united.
24th Parallel :
The line which Pakistan claims should be the demarcation between India and Pakistan.
38th Parallel :
Boundary between North Korea and South Korea.
49th Parallel :
Boundary between USA and Canada.
Natural borders are geographical features that present natural obstacles to communication and transport. Existing political borders are often a formalization of these historical, natural obstacles.
Some geographical features that often constitute natural borders are:
- Oceans: oceans create very costly natural borders. Very few nation states span more than one continent. Only very large and resource-rich states are able to sustain the costs of governance across oceans for longer periods of time.
- Rivers: some political borders have been formalized along natural borders formed by rivers. Some examples are; the Rio Grande border (Mexico-USA), theRhine border (France-Germany), and the Mekong border (Thailand-Laos)
- Lakes: larger lakes create natural borders. One example is the natural border created by Lake Tanganyika (Congo-Burundi-Tanzania-Zambia)
- Forests: denser jungles or forests can create strong natural borders. One example of a natural forest border is the Amazon rain forest (Colombia-Venezuela-Guyana-Brazil-Bolivia-Peru)
- Mountain ranges: research on borders suggests that mountains have especially strong effects as natural borders. Many nations in Europe and Asia have had their political borders defined along mountain ranges.
Throughout history, technological advances have reduced the costs of transport and communication across these natural borders. This has reduced the significance of natural borders over time. As a result, political borders that have been formalized more recently — such as those in Africa or Americas — typically conform less to natural borders than very old borders — such as those in Europe or Asia — do. States whose borders conform to natural borders are, for similar reasons, more likely to be strong nation-state.
The list below contains examples of rivers and lakes that are the bases of recent boundary disputes.
- Amazon and Maranon rivers (Ecuador and Peru)
- Armur River (China and Russia)
- Atrak River (Kyrgyzstan and Tajikistan)
- Belesa-Mareb-Setit Rivers (Eritrea and Ethiopia)
- Caspian Sea (Azerbaijan, Iran, Kazakhstan, Russia, and Turkmenistan)
- Congo/Zaire River (Democratic Republic of Congo and Republic of the Congo)
- Essequibo River (Guyana and Venezuela)
- Ganges-Brahmaputra-Meghna rivers (India and China)
- La Plata River (Brazil and Uruguay, and Brazil and Paraguay)
- Lake Chad (Cameroon, Chad, Niger, and Nigeria)
- Lake Malawi (Malawi and Tanzania)
- Lake Tanganyika (Democratic Republic of the Congo, Zambia, and Tanzania)
- Linyanti River (Botswana and Namibia)
- Maroni River (Suriname and French Guiana)
- Mekong River (Laos and Thailand)
- New River (Guyana and Suriname)
- Orange River (Namibia and South Africa)
- Sara and Una rivers (Bosnia-Herzegovina and Serbia, and Hungary and Slovakia)
NATURAL BORDER BY REGIONS:
- Bahr al-Arab: Sudan and South Sudan
- Congo River: Democratic Republic of Congo and Republic of Congo
- Chobe River: Namibia and Botswana
- Donga River: Nigeria and Cameroon
- Limpopo River: South Africa and Botswana
- Limpopo River: South Africa and Zimbabwe
- Orange River: Namibia and South Africa
- Yobe River: Niger and Nigeria
- Zambezi: Namibia and Zambia
- Zambezi: Botswana and Zambia
- Zambezi: Zimbabwe and Zambia
- Colorado River (Arizona-Sonora): United States and Mexico
- Detroit River: United States and Canada
- Halls Stream: United States and Canada
- Monument Creek: United States and Canada
- Niagara River: United States and Canada
- Pigeon River: United States and Canada
- Rainy River: United States and Canada
- Rio Grande: United States and Mexico
- St. Clair River: United States and Canada
- St. Croix River: United States and Canada
- St. Francis River: United States and Canada
- St. John River: United States and Canada
- St. Lawrence River: United States and Canada
- St. Marys River: United States and Canada
North America-Central America
- Hondo River (Belize): Mexico and Belize
- Suchiate River: Mexico and Guatemala
- Usumacinta River: Mexico and Guatemala
- Coco River: Nicaragua and Honduras
- Paz River: Guatemala and El Salvador
- Motagua: Guatemala and Honduras
- San Juan River: Nicaragua and Costa Rica
- Sarstoon River: Guatemala and Belize
- Sixaola River: Costa Rica and Panama
- Rapirrán: Brazil and Peru
- Rapirrán: Brazil and Bolivia
- Parana:Brazil and Paraguay
- Parana:Argentina and Paraguay
- Paraguay River: Brazil and Paraguay
- Paraguay River: Argentina and Paraguay
- Pilcomayo River: Argentina and Paraguay
- Bermejo: Argentina and Bolivia
- Ardila River: Spain and Portugal
- Danube: Austria and Slovakia
- Danube: Hungary and Slovakia
- Danube: Croatia and Serbia
- Danube: Serbia and Romania
- Danube: Romania and Bulgaria
- Daugava River: Latvia and Belarus
- Drava: Croatia and Hungary
- Drina: Bosnia and Herzegovina and Serbia
- Grense Jakobselv: Norway and Russia
- Guadiana: Portugal and Spain
- Kolpa: Croatia and Slovenia
- Lusatian Neisse: Germany and Poland
- Maritsa: Greece and Turkey
- Meuse: Belgium and The Netherlands
- Minho: Portugal and Spain
- Moselle: Germany and Luxembourg
- Mura: Croatia and Slovenia
- Narva: Estonia and Russia
- Neman River: Kaliningrad Oblast and Lithuania
- Oder: Germany and Poland
- Paatsjoki (Pasvikelva): Norway and Russia
- Prut : Romania and Moldova
- Rezovo: Bulgaria and Turkey
- Rhine: Germany and Switzerland
- Rhine: Germany and France
- Rhine: Switzerland and Liechtenstein
- Sava: Bosnia and Croatia
- Sava: Croatia and Serbia
- Tana River (Norway): Finland and Norway
- Tisza: Hungary and Ukraine
- Torne: Sweden and Finland
- Amur River: People's Republic of China and Russia
- Brahmaputra River: India, Bangladesh and China
- Ganges River: India and Bangladesh
- Indus River: India and Pakistan
- Kaladan River: India and Myanmar
- Mekong River: Laos and Thailand
- Naf River: Bangladesh and Myanmar
- Pandaruan River: Malaysia and Breuni
- Yalu River: North Korea and People's Republic of China
- Akhurian River: Armenia and Turkey
- Aras River: Armenia and Turkey
- Aras River: Nakhchivan (Azerbaijan) and Turkey
- Jordan River: Israel and Jordan
- Khabur (Tigris): Iraq and Turkey