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Portrait of Longest river

Geography · Records & extremes

Longest river

Africa and South America — the Nile against the Amazon

The one geography record with no settled answer. On the conventional figures the Nile wins at about 6,650 km against the Amazon's 6,400, and that is what most reference works still print. But the Amazon's length depends entirely on which Andean headstream is called the source and where its vast estuary is said to end, and Brazilian and Peruvian surveys since 2007 have made claims above 6,800 km. The honest answer is that it depends on the measuring convention, and quiz setters usually expect the Nile.

How to spot them

  • ▸A record where the standard answer and the challenger's answer are both defensible
  • ▸Quiz clue: 'Apurímac', 'Mantaro', 'Nevado Mismi', 'Kagera', 'Marañón'
  • ▸The winner by volume is not the winner by length — one carries about a fifth of all river water on Earth
  • ▸The dispute turns on where a source is and where an estuary ends, not on bad surveying

Key facts

The usual answer runs about 6,650 km from East Africa to the Mediterranean

The Nile, measured from the headwaters of the Kagera in Burundi or Rwanda

The challenger runs about 6,400 km on the same conventions, but far more on others

The Amazon, traditionally measured from the Apurímac and the glacier of Nevado Mismi in Peru

A 2007 Brazilian survey claimed a new source and mouth that put the South American river ahead (2007)

INPE and IBGE gave a figure around 6,800 km, measuring to the Pará estuary

A rival Peruvian headstream claim would add a further 70-odd kilometres

James 'Rocky' Contos argued in the 2010s for the Mantaro rather than the Apurímac

Whichever is longer, the South American one carries about twenty times more water

Roughly a fifth of all the river water reaching the world's oceans

The dispute is about convention, not measurement: where a source starts and an estuary ends

Seasonal and ephemeral headwaters, and a mouth over 300 km wide, make the question partly arbitrary

Third place is not disputed: a Chinese river of about 6,300 km

The Yangtze, the longest river to flow entirely within one country

Quick-fire facts

  • •Conventional figures: the Nile about 6,650 km, the Amazon about 6,400 km, the Yangtze about 6,300 km
  • •The Amazon's length depends on which Andean headstream counts as the source — the Apurímac or the Mantaro — and whether the Pará estuary and Marajó channel are included
  • •Brazilian researchers announced a figure of roughly 6,800 km for the Amazon in 2007, which would put it first
  • •The Amazon is undisputedly the largest river by discharge, at around 209,000 m³ per second — about a fifth of global river flow
  • •The Nile's main tributaries are the White Nile, rising in the East African lakes, and the Blue Nile, rising at Lake Tana in Ethiopia
  • •The Yangtze is the longest river to run entirely within a single country
  • •Common misconception: there is no internationally agreed authority that rules on river length, so 'the longest river' has no official answer
  • •In practice UK quizzes, including University Challenge, still take the Nile as the standard answer

Drill it — 8 cards

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Sources