The odder a border looks on a map, the better the story behind it. Almost all of the strange ones fall into four categories.
Straight lines drawn by empires
Roughly a third of Africa's international borders follow straight lines or lines of latitude and longitude. They were negotiated by European powers at conferences — most infamously the Berlin Conference of 1884–85, which formalised the "Scramble for Africa" — with almost no regard for the ethnic, linguistic, ecological or economic realities on the ground. The Egypt–Sudan, Libya–Chad, Libya–Egypt, Namibia–Botswana, Mali–Mauritania and Algeria–Mali borders are all largely ruler-straight. The same is true of many Middle Eastern borders drawn by Britain and France after the First World War (the Sykes–Picot line). The consequence — communities split across borders, and unrelated peoples grouped inside one — still drives conflict today.
Panhandles and corridors
- The Caprivi Strip — a thin finger of Namibia, about 450 km long, reaching east to touch the Zambezi River. Germany negotiated it from Britain in 1890 (trading Zanzibar and Heligoland) in the hope of a navigable route linking its colony of German South West Africa to the Indian Ocean. The Zambezi turned out to be blocked by Victoria Falls and unnavigable, so the strip achieved nothing.
- The Wakhan Corridor — a narrow arm of Afghanistan, in places under 15 km wide, that separates Tajikistan from Pakistan and reaches to touch China. It was created deliberately in 1893 as a buffer zone between the expanding British and Russian empires, so their territories would not directly meet.
- The Panhandle of Oklahoma, the Florida Panhandle, the Alaska Panhandle — all leftovers of compromises over state and colonial lines in North America.
Rivers that moved
Many borders follow the middle of a river, and rivers wander over time. Where the Rio Grande shifted its course, parcels of land ended up on the "wrong" side of the US–Mexico border, producing disputes like the Chamizal, which took from 1864 to 1963 to settle. The Ohio River border between several US states runs along the historic low-water mark on the northern bank, not the middle, for historical reasons — so the river itself is entirely within Kentucky, Ohio and West Virginia in places.
Enclaves you can only reach through another country
- Point Roberts, Washington — a small piece of the US at the tip of a peninsula that dips below the 49th parallel; you can only drive there through Canada. Its children are bused to school through Canada and back.
- Llívia — a Spanish town of about 1,500 people entirely surrounded by France, left to Spain by a 17th-century treaty that transferred villages but not towns.
- Büsingen am Hochrhein — a German village entirely surrounded by Switzerland; it uses the Swiss franc and is in the Swiss customs area.
- Baarle — the extreme case, with about 30 Belgian exclaves inside the Netherlands and Dutch counter-exclaves inside those.
The full explainer on countries inside countries, and the difference between an enclave and an exclave.
More on enclaves →The quadripoints and the missing ones
There is exactly one undisputed international quadripoint — a single point where four countries meet — and it is the meeting of Zambia, Zimbabwe, Botswana and Namibia at Kazungula on the Zambezi, though even this is disputed by surveyors who argue it is really two tripoints a few hundred metres apart. The United States has a clean four-state quadripoint (Utah, Colorado, Arizona, New Mexico) marked by the Four Corners Monument, but international ones are almost nonexistent because borders rarely line up that neatly.