Where is the true source of the River Amazon?

Searching Wikipedia, it suggests the River Apurímac has traditionally been considered the source. However, Google says it is the River Mantaro. In other places it is suggested it is the Nevado Mismi.

So which of these (if any) is the true source of the Amazona? Where is the river born?

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    $\begingroup$ Welcome to ES.stackexchange. "Google says"? Google searches different websites and prints out the search results. When I (US-english language configuration; German IP; Firefox) copy the "Google says" URL into my browser, text from the English Wikipedia is cited (same URL as the one posted by you). In the English Wikipedia article it is stated that "Apurímac River" had been considered as most distant source until 2014. Since then, Mantaro River is considered as such. Please edit your question accordingly. $\endgroup$ Commented Oct 4, 2017 at 6:43
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    $\begingroup$ As @Spencer wrote in his answer, please specify which source you mean (e.g. highest transported amount of water or most distant). There is a reference provided in the Wikipedia article to Contos and Tripcevich (2014). It is open access. $\endgroup$ Commented Oct 4, 2017 at 7:01
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    $\begingroup$ @daniel.neumann, certainly agree, but do see where his confusion comes from. I just verified, if you ask any of Google's voice assistants, it will just tell you the source is Montaro River. The fact Google started attempting to summarize info into simpler nuggets makes it basically its own answer. Indeed this is as much a reflection on the poorness of Google's product as it is true confusion. That said, especially given the uncertainty stated in the Wikipedia article itself, it seems a very reasonable question to me (even as I totally agree it's really trying to define something needlessly) $\endgroup$ Commented Oct 4, 2017 at 8:39
  • $\begingroup$ James, just wondering where it is typical to put the order as River <River Name>? $\endgroup$ Commented Oct 4, 2017 at 22:48
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    $\begingroup$ @JeopardyTempest english.stackexchange.com/questions/69657/… $\endgroup$
    – Spencer
    Commented Oct 6, 2017 at 22:11

1 Answer 1


From an Earth Science standpoint, it's meaningless to ask about the "source" of a river in this way. The "source" of a river is the rainfall within its drainage basin, which percolates down into groundwater, and the "river" appears where the land has eroded down below the water table.

The Amazon has an enormous drainage basin:

and every point in it is its "source" in some way.

The trouble with your question is that it asks about the "source" of a river in a way that you first have to define what you consider the "source". Does a stream begin where its name begins? Where water first permanently flows above ground? Most of the time? Some of the time? Anywhere there's a big enough pile of wet leaves?

In Brazil, the part of the river above its confluence with the Rio Negro at Manaus has its own name -- the Solimões, so you could say the "Amazon" proper begins at Manaus. But this is thousands of miles from the river's farthest upper reaches.

The Wikipedia article on the Amazon River has the following to say about its "farthest source":

The headwaters of the Apurímac River on Nevado Mismi had been considered for nearly a century as the Amazon’s most distant source, until a 2014 study found it to be the Cordillera Rumi Cruz at the headwaters of the Mantaro River in Peru. The Mantaro and Apurímac join, and with other tributaries form the Ucayali River, which in turn meets the Marañón River upstream of Iquitos, Peru, to form what countries other than Brazil consider to be the main stem of the Amazon.

But because a tunnel associated with the Tablachaca Dam diverts water away from a big loop of the Mantaro River, effectively shortening it, all you'll ever get now is an argument about what's "really" the furthest source.

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    $\begingroup$ Where would you get to if you started "walking" upstream from the Amazon delta and always took the largest (averaged through seasons) tributary? $\endgroup$
    – Antonio
    Commented Jan 8, 2019 at 17:52
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    $\begingroup$ @Antonio An argument. $\endgroup$
    – Spencer
    Commented Jan 9, 2019 at 18:54

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