Why were there seemingly larger, more organised civilisations in the South American part of the American continent compared to the North before European colonisation and why did they not migrate North?

There is seemingly plenty of farmland and natural resources in NA, so why didn't, for example, the Inca or Aztec move further north or some other people migrant and establish larger polities there?

Another way to word it may be to ask why North American wasn't colonised more by SA tribes etc prior to the European effort.

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    South America does not start in Rio Grande. Maybe you can adjust the title of your question if you want to include aztecs on it. Besides that, one has to remember that North America was not an empty space waiting for settlers, if was full of other cultures. Same argument applies to Rome and central Europe. Roman empiere could not colonize territory of contemporary Germany or Poland even though the empire lasted many centuries and those territories where quite near.
    – Santiago
    Jul 3, 2023 at 13:32
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    Probably for the same reason that the ancient middle-eastern empires (which had similar technological and organizational levels) didn't colonize: They had already expanded to the limits their sort of society could manage. As far as migrating North went, there was a pretty difficult desert barrier to cross.
    – Mark Olson
    Jul 3, 2023 at 13:48
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    I think this is a great question. Why the SA/CA cultures never broke into the north? Neither by land nor sea? Very similar invasions and migrations occurred in Europe and Asia, and so why it didn't happen in the Americas is something to think about. I would love to answer this question but my reading/library doesn't have anything that would address this question. Hopefully we'll get a couple good answers posted here.
    – Smith
    Jul 3, 2023 at 14:29
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    It should be noted that civilisations similar to those of Mesoamerica existed in the Middle East for thousands of years before Europe reached an equivalent level of development - and not even deserts were needed to stop or slow the spread. I wouldn't expect things in America to go faster.
    – Pere
    Jul 3, 2023 at 14:42
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    Hard to prove a negative, but the lack of draft animals could have been a factor.
    – SJuan76
    Jul 3, 2023 at 18:43

2 Answers 2


It wasn't worth the effort

This comes close to the question why the Roman Empire didn't take over Ireland or Germany: there was nothing there that warranted the effort; the costs would be prohibitive. Admitted, the Romans did try to integrate parts of Germany, but failed.

This applies even more for American civilizations because they lacked three vital necessary components:

  • No wheel

That means everything you need to get there or from there to bring home would have to be carried by men or animals. Which they also lacked:

  • No pack animals

The Incas had llamas, but the Mesoamericans didn't even have that. That means everything had to be man carried. No matter how you try justify it, that is really expensive.

  • No seaworthy ships

Having boats is one thing, seaworthy ships useful for carrying loads economically is quite another. The Mayas had boats, but nothing remotely close to viking longships or Roman ships.

Physical boundaries

Meso-Americans were restricted by deserts. First they had to cross the deserts in the north of Mexico, then cross the same deserts north of the Rio Grande to reach the Puebloans. They probably knew Puebloans existed, but it's doubtful if Meso-Americans knew civilizations beyond that. The Puebloans were far less developed than Meso-Americans, and lived in oases in canyons. I'm not sure if they would be seen as worthwhile for conquest or settlement.

And they would face the exact same limitations: no grains (they had corn, but but not wheat), no large animals, no metals, no wheel, no ships.

Further south the Inca empire had another barrier: the Darien Gap. That's one of the most rugged places on the planet. Steep mountains, vast jungles, dangerous animals and ferocious local tribes. Even today, with our modern technology there is no Pan-American Highway: it stops before the Darien Gap, and continues afterwards. But nothing in between. It still is too dangerous.

In the unlikely event Incas would send expeditions across the Darien Gap, they would be meeting the Meso-Americans. No idea how that would work out. I don't think that meeting would be a happy one for both parties. Perhaps for one party: 'Great, fresh sacrifices walking in.' or 'Looks neat here. We found what we need.' But not for both.

In both cases (Meso-Americans and South Americans) they had no need to expand due to population pressure. The Mayas did have a population problem but never solved it.


'Why didn't X happen?' questions are inherently speculative, so in that spirit, here's my wild, uninformed speculations...


For Central American states, invading North America would mean moving armies through relatively arid and/or mountainous regions in what is now the Southwestern US. These areas were largely inhabited by hunter-gatherers, and it would have been impossible for an army of any size to live off the land (no crops to pillage). The Mesoamericans didn't have access to pack animals, so it would have been difficult to carry enough supplies to reach farming regions further north. The South American cultures did have pack animals, but they would have had to cross the Darien Gap, which is difficult to do even today. Neither cultures were seafarers, so they couldn't move forces in that way either.


You're right that the major cultures of Central and South America were more organised, in that they had cities, monumental stone buildings etc. But I'm not sure they necessarily had a significant military advantage over the North Americans. For example, they didn't have metal weapons, or cavalry. They could presumably have organised larger armies than many North American groups, but then they couldn't necessarily support them on long-distance expeditions of conquest (see 'Logistics' above!)

Ultimately, I'd argue that conquering North America is just fundamentally difficult... after all, it took the Europeans several hundred years, even with the help of firearms and smallpox!

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    I would add one more reason: "need". The spanish conquistadors could have conquered north america, but why? With no cities to plunder, no known gold or silver mines to exploit, what would a mostly desertic plane full of savage hunter-gatherers offered to conquerors? Land? They had already more than they could control, and of better quality. There's a reason why the people from the euro-asian steppes invaded the civilized parts and not the other way around: economic incentives.
    – Rekesoft
    Jul 4, 2023 at 12:07
  • That's an excellent answer, but incomplete! The other parts are the need issue @Rekesoft notes in a comment and the fact that we have no record anywhere of societies at a similar level of development being able to conquer and hold that much territory. The surprise would be if they had conquered NA!
    – Mark Olson
    Jul 4, 2023 at 14:10
  • Yes fair points - it also links in to the point about trade routes and the flow of information... the whole reason Europeans came to America in the first place was because they knew about East Asia and were trying to find a new route there. For whatever reason, those types of links never developed in the Americas... don't really feel I have the background knowledge to do justice to these points however, maybe someone else who has read Jared Diamond can chime in :-D
    – JayFor
    Jul 4, 2023 at 15:28
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    This question does not require a Greater Aztec Empire stretching from Mexico City to Ohio. It would be enough if a group of mexicans founded a city in Texas, prospered, even if politically they become independent due to logistics, and then, in a few generations, they dominated Texas. Interestingly, the answer is still valid: with no ships, no good logistics, no vastly superior tech, they could not move enough people to really dominate NA tribes. Even IF they had sent a small expedition to explore or trade, it did not matter in the long run.
    – Luiz
    Jul 4, 2023 at 23:12
  • @Luiz That's exactly what happened. The Tejanos of northern Mexico allied with the mostly American colonists and broke away from Mexico creating the country of Texas. Texas then later joined the USA. The reason they could do this was due to the vast empty desert between the northern parts of Mexico and the civilised south, they'd been left to fend for themselves for so long and it wasn't until their work had achieved a reasonable standard of living in the north that Mexico City became interested in them politically and wanted control. Jul 5, 2023 at 21:32

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