Drainage basins of the world’s longest rivers
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Most of our planet’s surface is covered in water, but less than 1% of it is fresh water. The total water volume in rivers is measured at 2,120 cubic kilometers (510 mi³), or just 0.49% of the surface fresh water on the planet!
But despite this fact, rivers have played and still play a notable role in the development of civilization.
Rivers are the result of many compounding water inflows accumulated within a drainage basin. A drainage basin is defined as the land area where precipitation gathers and drains off, feeding rivers and their tributaries.
The map below created by Reddit user CountZapolai shows how large the drainage basins can be for the world’s longest rivers.
The longer a river system becomes, the more territory it passes through. As a result, long rivers have extensive drainage basins.
Below are the list of the world’s top 30 longest rivers and the size of their drainage basins:
| Rank | River | Length in km (miles) | Drainage area in km2 (mi2) | Outflow |
|---|---|---|---|---|
| 1 | Nile | 6,650 (4,130) | 3,254,555 (1,256,585) | Mediterranean |
| 2 | Amazon | 6,400 (3,976) | 7,000,000 (2,702,703) | Atlantic Ocean |
| 3 | Yangtze | 6,300 (3,917) | 1,800,000 (694,981) | East China Sea |
| 4 | Mississippi | 6,275 (3,902) | 2,980,000 (1,150,579) | Gulf of Mexico |
| 5 | Yenisei | 5,539 (3,445) | 2,580,000 (996,139) | Kara Sea |
| 6 | Yellow River | 5,464 (3,395) | 745,000 (287,645) | Bohai Sea |
| 7 | Ob–Irtysh | 5,410 (3,364) | 2,990,000 (1,154,440) | Gulf of Ob |
| 8 | Río de la Plata | 4,880 (3,364) | 2,582,672 (997,171) | Río de la Plata |
| 9 | Congo | 4,700 (2,922) | 3,680,000 (1,420,849) | Atlantic Ocean |
| 10 | Amur | 4,444 (2,763) | 1,855,000 (716,216) | Sea of Okhotsk |
| 11 | Lena | 4,400 (2,736) | 2,490,000 (961,390) | Laptev Sea |
| 12 | Mekong | 4,350 (2,705) | 810,000 (312,741) | South China Sea |
| 13 | Mackenzie | 4,241 (2,637) | 1,790,000 (691,120) | Beaufort Sea |
| 14 | Niger | 4,200 (2,611) | 2,090,000 (806,950) | Gulf of Guinea |
| 15 | Brahmaputra-Ganga | 3,969 (2,466) | 1,320,000 (509,655) | Bay of Bengal |
| 16 | Murray | 3,672 (2,282) | 1,061,000 (409,653) | Southern Ocean |
| 17 | Tocantins | 3,650 (2,270) | 950,000 (366,795) | Atlantic Ocean, Amazon |
| 18 | Volga | 3,645 (2,266) | 1,380,000 (532,819) | Caspian Sea |
| 19 | Indus | 3,610 (2,250) | 960,000 (370,656) | Arabian Sea |
| 20 | Euphrates | 3,596 (2,236) | 884,000 (341,313) | Persian Gulf |
| 21 | Yukon | 3,185 (1,980) | 328187 (328,187) | Bering Sea |
| 22 | São Francisco | 3,180 (1,976) | 610,000 (235,521) | Atlantic Ocean |
| 23 | Syr Darya | 3,078 (1,913) | 219,000 (84,556) | Aral Sea |
| 24 | Salween | 3,060 (1,901) | 324,000 (125,097) | Andaman Sea |
| 25 | Saint Lawrence | 3,058 (1,900) | 1,030,000 (397,683) | Gulf of Saint Lawrence |
| 26 | Rio Grande | 3,057 (1,900) | 570,000 (220,077) | Gulf of Mexico |
| 27 | Danube | 2,888 (1,795) | 817,000 (315,444) | Black Sea |
| 28 | Irrawaddy | 2,809 (1,745) | 404,200 (156,062) | Andaman Sea |
| 29 | Zambezi | 2,740 (1,703) | 1,330,000 (513,516) | Mozambique Channel |
| 30 | Amu Darya | 2,620 (1,628) | 534,739 (206,464) | Aral Sea |
The Amazon river has the largest basin globally, comprising 1/3 of South America. The tens longest rivers of the planet covering a land area similar to the size of Africa.