On earth we have relatively well defined national borders. But for off world colonies on places such as the moon, mars & titan, very little would matter outside of military bases, mines & spaceports. How would this impact how borders work? Would it be like Rimworld were there are randomly placed instillations from different nations all over a planet or would the instillations be somewhat grouped together based on nations. Would the concept of a border even really exist off world. Most of the industrial capacity & population is on earth still but the colonies are relatively independent food wise. War happens off world & is relatively frequent. All the colonies are controlled by earth nations outside of a few exceptions.

(note: there is no terraforming & no one has left the solar system)

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    $\begingroup$ There is no hard and fast rule of how borders between sovereign powers are to be arranged. (1) The present day state of nice rounded contiguous nation states is exceedingly modern, dating only since about 1800 or so; it's much too soon to tell whether it will continue far into the future. (2) A sovereign country and a nation are two different things; the present day state of countries being roughly coextensive with nation is both extremely modern (since the late 19th and early 20th century) and far from universal (see, e.g., Russia and China). (3) It depends on the story you want to tell. $\endgroup$
    – AlexP
    Jul 25, 2021 at 10:36
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    $\begingroup$ I tried to answer this Q, but I had to VTC:TSB. Borders come about due to language, culture, politics, greed for resources, and a thousand other things - but by the time space-faring capabilities come around, there will exist a body of international law fundamentally governing how expansion can occur. The nature of that international law is up to your story. Whether or not colonies are nationally-based, corporate-based, or hardy individuals who don't consider themselves subject to that law is up to your story. I don't believe this Q has an objective best answer without explaining the story. $\endgroup$
    – JBH
    Jul 25, 2021 at 14:57
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    $\begingroup$ VTR: I don't see how this query is about plot, character development or narrative arc. @JBH -- You said that borders arise because of * language, culture, politics, greed for resources, and a thousand other things* all of which are a function, first and foremost of the fictional world. As with laws of physics, there are laws of sophont behaviour. Normally I find myself in agreement with you, but I can't rationalise how the creation, determination & enforcement of borders is dependent on the narrative flow. I see this as a fundamentals of world query. $\endgroup$
    – elemtilas
    Jul 25, 2021 at 17:27
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    $\begingroup$ I think this is actually a good query. This is a reality that we are soon going to be facing right here in the real world, as we have nations that are not only rivals on the planet but also in space. We already have a terrestrial analogue --- Antarctica --- which, like a desolate planet, is divvied up by the Great Exploratory Powers. Studying the various Antarctic treaties and how they came about might be a good road for you follow. $\endgroup$
    – elemtilas
    Jul 25, 2021 at 17:30
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    $\begingroup$ @elemtilas Every war in history is an exception to what you explained. And the only reason there have been no "border disputes" in Antarctica is because there's nothing there anyone wants outside of scientific value that wouldn't lead to international problems had the borders been challenged. How can we determine what will happen with interstellar colonial law or behavior without the OP's input? Any law we have on the books today won't mean a thing if the colony has an ounce of secrecy. I read the other answers - they're very optimistic about the predictability of the situation. $\endgroup$
    – JBH
    Jul 25, 2021 at 19:04

7 Answers 7


On earth we have relatively well defined national borders

No, we really don't. There's hundreds of poorly defined or contested borders

Your borders will initially be implicit (each point on the surface will belong to the closest installation). Forming a voronoi graph.

enter image description here

Eventually a treaty will be arranged declaring the border to follow a natural feature or explicitly giving one side a resource.

See also this answer

  • $\begingroup$ Can you give the reference for the script producing the gif you used? $\endgroup$
    – L.Dutch
    Jul 25, 2021 at 11:38
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    $\begingroup$ @L.Dutch worldbuilding.stackexchange.com/a/195889/78800 Which links to the original source (which is wikipedia), $\endgroup$
    – Ash
    Jul 25, 2021 at 11:54
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    $\begingroup$ While not entirely incorrect, this is greatly oversimplified. In reality, the rate of expansion is non-uniform in both space and time, with natural borders such as rivers and inhospitable land (mountains, deserts) serving to slow expansion, desirable land serving to speed it, and different polities expanding at different rates. Also, every settlement is potentially its own "hub", which may be part of a larger polity. Which is why real maps don't much resemble Voroni diagrams. (Con't...) $\endgroup$
    – Matthew
    Jul 25, 2021 at 12:41
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    $\begingroup$ "Which is why real maps don't much resemble Voroni diagrams." Maybe not on Earth, but things might be different when we start settling other planets. You might see something like the state boundaries in Australia, which are rather voronoi diagram-like, centered around the capital cities. $\endgroup$
    – nick012000
    Jul 26, 2021 at 7:40
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    $\begingroup$ i think the biggest problem with that aproach is to assume that there wouldn't be border friction at first. everybody will want some key spot and in our day and age it's pretty unlikely we would let this kind of thing happen without first slapping some reegulation (even if not alway respected.) it would only work if settlement were placed at random point $\endgroup$
    – shas
    Jul 26, 2021 at 13:48

The concept of the state is only as strong as the collective will of all of the political divisions involved. On Earth, no state exists but by collective treaty and the consensus of the majority of political entities.

It is commonly held that the Western state system, the idea of sovereignty within defined borders, arose out of the Peace of Westphalia, a series of treaties agreed to by several European political entities, around 1648. Before that consensus agreement (the Catholic Church never did accept it - the Catholic church believed all land belonged to God, and thus to the Church as God's steward), territoriality was pretty much established by might, and the size of the army one could muster. The concept of "that one could' pretty much encompassed all variations of 'that one could'. Strongmen, criminals, warlords, kings, religious leaders, charismatic charlatans, cults, could all claim 'territory' if they were powerful enough. Previous to the Peace of Westphalia, there was no real concept of land 'ownership' in the 'West' (read: territory of the white man) except that of "Squatters' Rights", and 'you own what you kill'.

It is only when the slaughter became so extreme, and the economic impact so volatile, as in the Hundred Years War, that Westernized humans were forced by economic necessity to seek treaties with each other and to agree on defined boundaries.

However, now that the concept of granting 'political sovereignty' to established political entities has been universally established on Earth, and 'taxation within sovereign boundaries' has become entrenched in socio-economic principles, the idea of 'statehood' has become self-sustaining. The notion that territorial boundaries are defined by treaties between neighboring political entities has become generally accepted, the Crimea and Kashmir excepted.

In Asia, on the other hand, the concept of 'statehood', 'nationality', and 'sovereignty' has evolved very differently, over 8,000 years of a continuous historically contiguous singular society.

Indigenous societies, as exemplified by the Iroquois Confederacy, have also solved the sovereignty problem in a very different way - nomadic sovereignty not defined so much by territory, but by tribal affiliation and tribal rights. One is bound collectively by all 'nations' through tribal association, not by where one resides. A very different concept than 'citizenship by territory', more akin to the philosophical discussion 'Is being Jewish a religion, a nationality, a racial identity, or a birthright?'

The TL:DR is that borders, territorial boundaries, and political entities of new off-Earth lands will likely evolve and be finally resolved by treaties and agreements between the neighbours, rather than by some grand design.

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    $\begingroup$ "In Asia, on the other hand, the concept of 'statehood', 'nationality', and 'sovereignty' has evolved very differently, over 8,000 years of a continuous historically contiguous singular society." Really? I'm pretty sure that China's had a number of ups and downs over the years where they got conquered by barbarians that became the new ruling class. $\endgroup$
    – nick012000
    Jul 26, 2021 at 7:37
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    $\begingroup$ "China has NEVER been 'conquered' by 'invading barbarians' or anyone else, except the British, (and briefly the Japanese during WWII)" And the Mongols, and all the other nomadic plains tribes that conquered them. They built the Great Wall for a reason. The Mongols were the most successful, since they then proceeded to build an empire across Asia, the Middle East, and Europe, but they weren't the only ones, IIRC. $\endgroup$
    – nick012000
    Jul 26, 2021 at 14:42
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    $\begingroup$ Also, describing China's history as "a historically contiguous singular society" is also disingenuous because IIRC there were also a number of time periods where what is now China was fragmented into multiple states (for instance, during the time of Genghis Khan). $\endgroup$
    – nick012000
    Jul 26, 2021 at 14:49
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    $\begingroup$ @nick012000 Historical revisionism. During every one of those periods, the 'leaders' or 'rulers' changed, but the culture did not. The language evolved, but it is still understandable in terms of precedent and style. Archeological artifacts can be assigned to various dynasties, but the 'culture' is continuous and contiguous. Genghis Khan was a Mongol, but by the time of the Yuan dynasty, it was almost exclusively Han Chinese in nature. The Yuan dynasty was more a civil disruption and dynasty change by the Han Chinese themselves, rather than an external conquest. No cultural disambiguation. $\endgroup$ Jul 26, 2021 at 16:45
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    $\begingroup$ @JustinThymetheSecond I'd be interested to read some writings of historians on that topic, if you have any, since everything I've read about the topic so far disagrees with you. $\endgroup$
    – wizzwizz4
    Jul 26, 2021 at 17:23

They could run the moon bases like Antarctic bases.

The moon has a lot in common with Antarcica. Persons living there are vulnerable. It has not been developed or formally claimed. There is an interest by all parties that military instillations not be placed on the moon, an ounce of prevention being worth a pound of cure.

Antarctic Treaty

Activities in the Antarctic had generally been conducted peacefully and cooperatively. Yet the possibility that exploitable economic resources might be found meant the possibility of future rivalry for their control. Moreover, isolated and uninhabited, the continent might at some time become a potential site for deploying nuclear weapons...

In the years after World War II, as interest grew in keeping the continent from becoming militarized, there began diplomatic discussion of the possibility of formalizing a demilitarization arrangement. On May 3, 1958, the United States proposed to the other 11 nations participating in the IGY that a conference be held, based on the points of agreement that had been reached in informal discussions:

(1) that the legal status quo of the Antarctic Continent remain unchanged; (2) that scientific cooperation continue; (3) that the continent be used for peaceful purposes only.

... No insurmountable conflicts or issues divided the conference, and negotiations culminated in a treaty signed by all 12 nations on December 1, 1959...

The treaty provides that Antarctica shall be used for peaceful purposes only. It specifically prohibits "any measures of a military nature, such as the establishment of military bases and fortifications, the carrying out of military maneuvers, as well as the testing of any type of weapons." (The Treaty does not prohibit the use of military personnel or equipment, however, for scientific research or for any other peaceful purpose.) Nuclear explosions and the disposal of radioactive waste material in Antarctica are prohibited.

The Treaty provides for designation of observers to carry out inspections in all areas of Antarctica, including all stations, installations and equipment, and ships and aircraft at discharge or embarkation points. Each observer has complete freedom of access at any time to any or all areas of Antarctica... The United States has conducted 14 inspections since 1963.

For the first time, in 2012 the U.S teamed with another country to conduct joint inspections of third-party Antarctic stations. In January 2012, a team of four officials from the United States and four from the Russian Federation inspected research facilities operated jointly by France and Italy (Concordia), Italy (Mario Zucchelli), and New Zealand (Scott Base).

As I understand it the Antarctic treaty and system for cooperation and mutual enforcement has been applied to early space treaties and other situations where cooperation is key.


For a near-future setting in the solar system, look at the Outer Space Treaty.

For a far-future, interstellar setting, look at the concept of terra nullius and how modern and historical usage changed. Used to be that land with no inhabitants (at least none who counted as "civilized") could be seized by effective occupation. Expanding this concept to space gives you many interesting possibilities, and also sources of conflict and adventure.

  • Just how scarce are habitable/terraformable planets and how hard is it to reach them? If there are many planets within easy travel, there is less pressure to share planets. If there are few, various colonies might be placed on the same planet.

  • Once terraforming or the introduction of terrestrial species into an existing ecosystem becomes an issue, there can't really be more than one project per planet. Either the colonies cooperate, or there is only one colony, or it becomes a mess. It could be legally recognized that the first colony effectively claims the entire planet, but that might not be what you want for your setting.

  • Installations would come in a logical pattern -- power facilities, various mines and refineries, industry, agricultural areas if there are any. It does no good to have the iron ore on one side of the planet and the blast furnace on the other. Clusters where the various resources cluster might be more valuable than any one mine, no matter how rich.

If you want war in your setting, you might be able to promote that by setting strict requirements for effective occupation -- until they build on it, it isn't theirs can someone else can land-grab ...


I would expect any early settlement/colonisation to be haphazard, with everyone grabbing whatever they think is valuable and fighting (with violence, or in whatever political or judicial arena is available) over the legitimacy of their control.

Over time, control would be consolidated. Far-flung patchworks of installations would separate into distinct entities, lose parts to others’ control, take control of intervening ground, or all of the above. Stronger powers (perhaps political entities from Earth) would establish their authority over the weaker ones, if they didn’t have it already. Between the stronger powers, some form of consensus would emerge, tamping down most (but not all) disputes.

(The alternative is for a centralised or consensus authority to be behind the colonisation efforts from the beginning, but that’s boring!)

I base this on three kinds of historical precedent: colonial boundaries, farming/mining claims, and modern laws.

Colonial boundaries

Late in the colonial era, the major colonial powers had reasonably well-established rules for who held what and how to partition the land. It looks orderly, well regulated, almost civilised… until you remember that they were still conquering inhabited land.

Example: The Scramble for Africa. Literally the entire continent ended up assigned to one European nation or another (with the possible exception of Ethiopia, which remained independent except for a short Italian occupation in the 20th century.)

Earlier, though, the main determiner of colonial boundaries was what you could effectively hold. As a result, borders were… fuzzy. Sometimes a colonising power would claim a large area, but only effectively control small portions, so other powers would come in and settle their own colonies in the claimed area.

Example: The Treaty of Tordesillas established a Spanish claim to the entire New World (except a bit of South America that they may not have realised crossed the line). Great Britain, France, the Netherlands, et al. didn’t exactly care.

Other times the original power would extend their control through the territory they already claimed, typically splitting it into new colonies in the process.

Example: New South Wales, the British claim in Australia, started as half the continent and gradually had six new colonies split off from it (though one, North Australia, was promptly merged back in).

Sometimes colonising powers would claim land their explorers hadn’t even surveyed yet! Colonies might have a defined extent along the coast, and then stretch an indefinite distance inland along an effectively arbitrary line of latitude or longitude.

Example: Early British colonies in North America sometimes had charters “from sea to sea”, far beyond their actual control. This was wishful thinking, of course, but it seems like the first real modification came from French claims on the centre of the continent (which the French explored). The British colonies still extended much further west than any of them had actually settled until 1763. (After that it reversed, and colonists started settling further west than colonial authorities had claimed…)

And of course colonies would conflict with each other, dispute boundaries, claim each other’s lands, and just plain change hands. Even colonies of the same colonial power!

Example: See the links in the previous example for arguments between British North American colonies over who held what. Among the many colonies that changed hands are New France, New Netherland, Spanish Jamaica, Portuguese Bombaim, German New Guinea

Farming and mining claims

Just because a sovereign entity has claimed ground and fended off all challengers, doesn’t mean its use or ownership is settled. Someone has to actually go there and do something with it. Historically, there have been several occasions where individuals or groups could claim a chunk of land, typically for farming or mining purposes. This leads to all sorts of conflicts and shenanigans.


  • In the United States, several land runs (or rushes) opened up land to literally the first person to run (or ride a horse, or drive a cart) to it.
  • In Australia, similar (if less dramatic) allocations of land were made to selectors, which sometimes meant conflict with the unregulated squatters who had already been grazing livestock there.
  • During the US and Australian gold rushes, miners could claim land under rules that were generally accepted and enforced by the communities themselves. The governments later got in on the act, and to this day the ability to stake a “mining claim” exists in some form in both countries.
  • Of course, anywhere that you have claims, you have claim jumping—the attempt to take over another’s claim by force, subterfuge, or simply by moving in when the claimant fails to make use of the land.

Modern laws

These days there are a lot of rules over who owns what, and what “ownership” really means.

It was a long-established principle that whoever owns a piece of land also owns the underground below it and the air above it. Both of these are changing in modern times, though.

“The air above it” only became an issue in the age of air travel, and governments had to start coming up with air rights to say who can do what in the space above the ground.

In theory, I think it’s still the case that “the underground below” belongs to whoever owns the land. The problem there is that the real “owner” is the government (in England and some other Commonwealth realms, the Crown), and the householder living on the land just has a right to use it. I’m not a lawyer, but I believe the term for “really owning the land” is allodial title, whereas just having the right to use the land is “freehold”.

Off the coasts, the modern Law of the Sea establishes several zones of control with varying rules. (Who has the right to sail through? Who has the right to fish? Who can mine the seabed?)

I joked at the top about it being “boring” if state-like powers are in control from the beginning, but actually there’s still a lot of scope for conflict within this kind of rules-based regime.

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    $\begingroup$ "Literally the entire continent ended up assigned to one European nation or another." (whispers) They never got Ethiopia $\endgroup$
    – Qami
    Jul 26, 2021 at 18:21
  • $\begingroup$ @Qami: Depends on whether you count the 1936 fascist occupation or not! But that's a point worth noting anyway. $\endgroup$ Jul 27, 2021 at 13:56
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    $\begingroup$ @Qami: PS I just belatedly got the reference. $\endgroup$ Jul 27, 2021 at 14:05
  • $\begingroup$ Owning what is underground is has also become debatable... Many large companies lobbying/bribing for rights under residential areas have made it so that land owners in many areas are no longer allowed to own the oil, natural gas, water, minerals, etc. under their own properties so that local governments can literally sell your valuable resources right out from underneath you. In these places, to own the right to mine your own land, you must specifically purchase the mineral rights from your local government. $\endgroup$
    – Nosajimiki
    Jul 27, 2021 at 14:25
  • $\begingroup$ In some places it is even illegal to collect rainwater without the purchasing the mineral rights to your own land because it is seen as stealing from who ever owns the water table in your area. $\endgroup$
    – Nosajimiki
    Jul 27, 2021 at 14:26

if the colonisation was started with today paradygme there are a few different possibility

Capitalism baby

If you want to go for a route where it's mostly/only corporation doing the settlement there could be a system where any plot of land on your colony are up for grab for a fee at a regulatory agence that will keep a record of who claim what land. like that you don't need any settlement to buy a huge chunk of land you plan on mining.

it will allow for a more granular repartition of the territorry

big state and maritime law

If you want something involving big state we could probably keep something like what we curently have regarding maritime law, where for any settlement you get a an area of economic exclusivity all around it.

Like we are seing in the south china sea, it's a great way to have a lot of cold conflict. if you want to be a dick about it you can just build up settlement just for the sake of getting more area of controle


the most utopian of the outcome, but still a real possibility if the measure are taken before any mass scale colonisation start, it could all be administered by an IGO that prohibit any kind of spacial claim and administer at will what will be built where.


Natural Landscapes

Humans throughout history interested in peace have preferred to use natural landscapes to define territories: Rivers, mountain ranges, oceans, etc. On non-Earth worlds, this would still be the standard.

Even without any colonies on these worlds, humans have already started breaking up and naming regions; so, when our first colonies start to land on these bodies, initial claims will be made on the named regions where they originate. So, you may have one nation claim all of Mare Tranquillitatis and another claim all of Mare Sernitatius even though each nation can only put tiny outposts in these places... and this will be good enough for a while. Until one side or the other expands enough to for the exact line between the two places to matter, these will just be the generally accepted territories.

However, modern nations communicate WAY better than we did in past; so, instead of waiting until conflicts emerge as we have seen in most of history, modern nations would have the foresight to define exact boundaries before conflict emerge. In the interest in maintaining peace for future generations, when those first two colonies set down, there will likely be a few politicians from either nation taking a look at a picture of the moon. They will draw some line between the two Mares in what ever looks like the most logical physical point of separation and then agree that that is the boarder.

enter image description here


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