Random River Name Generator

How this random river generator works

Press Generate and you get a river. Turn up the Number box for several at once, no repeats. Copy takes them. The three filters trim before the draw and all of them ignore case.

Nile. Amazon. Mekong. Volga. Ganges. Rhine.

And a handful you have almost certainly never heard of. Kagera. Apurímac. Jefferson. Finlay. Chambeshi.

Those five are the most interesting rivers in the world, and not one of them is famous.

Where does a river begin?

It sounds like a question with an answer. It is not.

A big river is fed by hundreds of streams, which are fed by thousands of trickles, which come out of the ground in places that are wet in March and dry in September. There is no line on the land where a river switches on.

So geographers pick a rule, and there are at least four in use:

• Most distant point. Follow the longest continuous chain of channels back from the mouth. This is the most common rule.
• Greatest flow. Follow whichever branch carries the most water. By this rule the Blue Nile, which supplies most of the Nile's water, would have a strong claim over the White.
• Largest drainage basin. Follow whichever branch drains the most land.
• Highest spring. Follow whichever branch starts at the greatest altitude.

Four rules, four different sources, four different lengths for the same river. And a fifth complication on top: the rule usually says the source must flow all year round, which rules out any headwater that dries up in summer.

The Amazon does not have one source. It has three candidate headwater regions in the Peruvian Andes: the Marañón, the Apurímac, and the Mantaro.

Every river's length is measured from a tributary you have never heard of

This is the consequence, and once you see it you cannot unsee it.

The Nile is 6,650 kilometres long if you start at the Kagera, whose own headwater is in Burundi. Not at Lake Victoria, which is where the tourist maps start it. At a river in Burundi that almost nobody outside east Africa can name.

The Amazon is a certain length if you start at the Apurímac, high in the Peruvian Andes. The Mississippi is one river measured from Lake Itasca and a considerably longer one measured up the Missouri and then up the Jefferson. The Yenisei runs back through the Angara to the Selenge. The Mackenzie runs back through the Slave and the Peace to the Finlay. The Congo begins, officially, at the Chambeshi.

So every headline river length is a compound object: a famous river, plus a chain of anonymous ones, plus a rule for choosing which anonymous ones count.

Nobody hides this. It is simply not printed on the poster.

The longest river in the world is a matter of definition

Guinness World Records gives the title to the Nile, and then adds a note saying that which river is longer is more a question of definition than of measurement. That note is doing more work than the record.

Encyclopaedia Britannica puts the Nile at 6,650 kilometres and the Amazon at 6,400, measuring the Amazon from the headwaters of the Apurímac.

Change the starting point and the answer flips. In 2007 a Brazilian team announced a new source and, more controversially, a new mouth, running the Amazon out through the Pará on the south side of Marajó Island rather than the northern channel. That alone added several hundred kilometres.

Then in 2014 an American researcher argued that the most distant source is not the Apurímac at all but the Mantaro, which would add another seventy-odd kilometres.

Meanwhile there is the ruler problem. A river meanders. Measure it on a coarse map and you cut the corners. Measure it on a fine one and every bend adds length. Two people measuring the same river with the same rule and different maps will not agree, and neither of them is wrong.

So: the Nile, probably, by convention, and only if you agree on where it starts.

The Mantaro problem

The Mantaro's claim is the most interesting one in the argument, and it is not clean.

Its source has been measured as more distant from the Amazon's mouth than the Apurímac's. On the most-distant-point rule, that should settle it.

Except that the Mantaro runs dry for several months a year. It has done so ever since a dam built in 1974 began diverting its water through a tunnel to a hydroelectric plant.

Which puts the rule against itself. A source is supposed to flow all year round. The Mantaro does not, and the reason it does not is a dam. So does the source of the Amazon depend on a Peruvian engineering decision from 1974? If they demolished the dam tomorrow, would the Amazon get longer?

Those are not silly questions. They are what happens when a definition written for nature meets a river that people have rearranged.

Nobody has a good answer. That is the honest state of the subject, and a river generator may as well say so.

Ways people actually use this

• Geography lessons. Generate five and ask which continent each drains. The tributaries will trip up anyone who has only memorised the famous names.
• Quiz rounds. Show the tributary, ask for the river it feeds. Kagera is a hard question with a satisfying answer.
• Worldbuilding. A river is a road, a border, a water supply and a flood risk. Pick one and the map arranges itself around it.
• Naming things. Short, pronounceable, evocative, and mostly not taken.
• Deciding what to read about. Almost nobody knows what the Chambeshi is. It is where the Congo starts.

Getting more out of the filters

• Nearly every name is a single word, which makes Starts with unusually clean here. Pick a letter and you get a tidy set.
• Ends with a returns a large share of the list. Rivers ending in A are disproportionately Slavic, Iberian and South American, which is a real pattern and not a coincidence.
• Type River into Contains and almost nothing comes back. Rivers do not need the noun.
• If a filter returns fewer than you asked for, loosen it and run again.

Questions people ask

What is the longest river in the world?

The Nile, by convention and by Guinness World Records, at about 6,650 kilometres. The Amazon has a serious claim that depends entirely on which Andean headwater you accept as its source. Anybody who gives you one answer without mentioning the other has skipped a step.

Which river carries the most water?

The Amazon, and it is not close. It discharges several times more water than any other river on Earth. Length and volume are completely different questions and the Amazon wins one of them outright.

What is the Kagera?

The most distant headstream of the Nile, rising in Burundi and flowing into Lake Victoria. The Nile's official length is measured from it.

Why is it so hard to find a river's source?

Because a river does not have one. It has a network of tributaries, and choosing a source means choosing a rule: most distant, greatest flow, largest basin, or highest spring. Each rule picks a different stream.

Is the Missouri longer than the Mississippi?

The Missouri is longer than the stretch of the Mississippi above their confluence, yes. Which is why measuring the Mississippi from its own headwaters at Lake Itasca gives a much shorter river than measuring it up the Missouri.

References

1. Source of the Amazon River
2. Locating the source and mouth of the Amazon River
3. Is the Amazon longer than the Nile? An expedition aims to find out