Enclaves and Exclaves Explained: Why Some Countries Have Pieces Inside Other Countries

Most borders on a map look like what they are trying to be: a line separating one block of colour from another. Then you zoom in on a stretch of the Dutch and Belgian countryside and find a colour scattered into twenty odd fragments, with fragments of the other colour inside those. It looks like a printing error. It is a legal fact, and people live in it.

Territorial oddities of this kind are worth understanding for a reason beyond novelty. They expose how borders are actually made: not by geography deciding, but by inheritance, negotiation and paperwork, sometimes centuries ago and often somewhere very far away.

The definitions, kept clean

An enclave is territory that is completely surrounded by the territory of a single other state. An exclave is part of a state that is separated from the main body of that state, so that you cannot reach it without leaving and re-entering.

The words describe different relationships, which is why a piece of land can be one, the other, or both.

• An enclaved state is a whole country surrounded by one neighbour. Lesotho sits entirely within South Africa. San Marino and Vatican City sit entirely within Italy. These are enclaves but not exclaves, because there is no separated mainland elsewhere.
• A true enclave, sometimes called an enclaved exclave, is a fragment of country A wholly inside country B. Baarle-Hertog's parcels and the Spanish town of Llivia are the standard examples.
• A plain exclave is separated from its mainland but not surrounded by a single state. It may border two or more neighbours or have a coastline. Kaliningrad, on the Baltic, is the most cited European example, separated from the rest of Russia and bordering more than one country.
• A pene-exclave, or practical exclave, is attached by land but unreachable from home territory without crossing a frontier, usually because a mountain range or a river is in the way. Point Roberts, at the tip of a peninsula south of Vancouver, is a familiar case.

Only the first three matter for most conversations, and mixing up enclave and exclave is so common that it is worth the ten seconds: enclave is about being surrounded, exclave is about being detached.

Baarle-Hertog and Baarle-Nassau

The most extravagant surviving example sits on the Belgian and Dutch border. One town, two municipalities, and a boundary that cuts through streets, gardens and at least one building, marked in the pavement with metal studs and white crosses so residents can see it.

The cause is medieval. In the twelfth and thirteenth centuries, land in the area was divided between the Lord of Breda and the Duke of Brabant through a series of sales, swaps and inheritances that treated individual plots rather than contiguous blocks. When the Netherlands and Belgium became separate states in the nineteenth century, the negotiators inherited a parcel-by-parcel patchwork and were unable to rationalise it, so the medieval ownership map became an international frontier.

The result is unusually good-humoured. Both municipalities cooperate on services, houses take their nationality from the location of the front door, and the boundary is a tourist attraction rather than a grievance. It is a reminder that a complicated border is not automatically a contested one.

Llivia, a town left off a list

Llivia is a Spanish town of a couple of thousand people, sitting a few kilometres inside French territory in the eastern Pyrenees. Its existence traces to the settlement that followed the Treaty of the Pyrenees in 1659 and the arrangements made shortly afterwards, under which a group of villages in the Cerdanya was transferred to France.

Llivia was not a village. It held the status of a town, and the transfer as written covered villages, so it stayed Spanish while everything around it changed hands. A road now connects it to Spain across French land.

It is a small masterpiece of unintended consequence, and a useful warning about the gap between a category in a document and the ground it is supposed to describe. Borders written in one language, in a palace, about places the negotiators had never seen, produce exactly this.

Cooch Behar, and the largest untangling

The most complex enclave landscape of the modern era lay along the border of India and Bangladesh, around Cooch Behar. There were well over a hundred small enclaves, including enclaves inside enclaves, and at least one counter-counter-enclave: a piece of India inside a piece of Bangladesh inside a piece of India.

The origins lie in princely-era landholdings that predate the modern border, later frozen in place by the partition arrangements of 1947, when the line between the two states was drawn without unpicking the underlying patchwork. Residents faced practical difficulties that had nothing to do with novelty: reaching a school, a clinic or an official office could require crossing an international boundary.

The two governments negotiated a Land Boundary Agreement, ratified and implemented in 2015, which exchanged the enclaves and allowed affected residents to choose their citizenship. It is the clearest example available that these situations are solvable by ordinary negotiation when both sides want them solved.

How enclaves happen

Four mechanisms cover most cases.

Feudal and dynastic inheritance

Before territorial states, sovereignty attached to relationships and holdings rather than to blocks of land. Estates were split among heirs, sold, mortgaged and granted, producing a mosaic of who owed what to whom. When later states drew lines over that mosaic, the fragments survived. Baarle is the textbook case.

Treaties written at a distance

Negotiators worked from lists, coordinates and imperfect maps. A village named twice, a category applied loosely, a river assumed to run where it did not: each produces an anomaly that then has to be lived with. Llivia is the tidiest illustration.

Moving water

Rivers are popular boundaries because they are visible, and unreliable because they move. When a channel shifts, land can end up on the other side of a boundary that is legally fixed to the old course, creating detached parcels. This is a routine source of pene-exclaves along long river frontiers.

The end of empires

Decolonisation and imperial collapse converted internal administrative arrangements into international borders very quickly, often on a deadline. Anything unresolved on the day became permanent, which is how the Cooch Behar patchwork survived into the twenty first century.

Note what is missing from this list: geography. Enclaves are not made by terrain. But terrain does shape the borders that surround them, which is the subject of our pieces on deserts as natural borders and mountains as borders.

Living in one

The everyday consequences are mundane and relentless: which utility supplies your house, which post office serves you, which emergency number to call, which side of the street the school bus runs on. Solutions are usually local and pragmatic, built up by neighbouring authorities over decades.

Access is the recurring theme, which puts enclaves in the same family of problems as countries with no coast at all. We look at that in how landlocked countries trade. In both cases, a state's ability to function depends on arrangements with the neighbour whose territory sits between it and the rest of the world.

Borders as artifacts

The reason a fragment of Belgium inside the Netherlands is worth ten minutes of your attention is that it makes visible something every border shares and most borders hide. A boundary is a record of decisions made by particular people at a particular moment, for reasons that often no longer exist.

Straight lines look natural on a small map. Enclaves look absurd. In truth they are the same kind of object, and the absurd ones are simply the ones that never got tidied up. If you want more of this sort of thing, browse topics to see the range of geography and history we cover in short pieces.