Great rivers of the world
Rivers hold only about 0.0002 percent of Earth’s water, yet the Amazon alone carries about a fifth of all river water.
Longest, largest, fullest
Comparing rivers requires three different measures: length, drainage area and water flow. By length, the CIA World Factbook lists the Nile in Africa first at 6,650 kilometres and the Amazon second at 6,436. By drainage area, the Amazon is first by a wide margin; the National Geographic Information Institute of Korea calls it the largest river by basin area. By the amount of water, the Amazon wins again: the NGII’s national atlas says it carries about 20 percent of the world’s river water to the sea. The Mississippi’s basin, the third largest, is small next to it.
Length is harder to measure than it sounds. A river’s length depends on which tributary you treat as the source and where exactly the mouth is drawn in a delta or estuary, and different surveys disagree by tens or hundreds of kilometres. The Nile and the Amazon differ by about 214 kilometres in the Factbook figures, close enough that the order depends on how the two rivers are measured. Areas of basins and the flow of water are measured differently again. When a book says a river is the biggest, check which of the three it means.
Rivers that made civilisations
People settled along rivers long before they built cities, and the NGII atlas lists the great Asian rivers that carried that story: the Yangtze, Asia’s longest; the Huang He, which carries fine yellow silt; the Mekong, longest in Southeast Asia; the Tigris and Euphrates of the Fertile Crescent; and the Indus and Ganges of South Asia. Floods spread fertile silt over the land each year, and the rivers were also roads. The same atlas names other famous rivers for different reasons: the Colorado, which carved the Grand Canyon; the Rhine, the lifeline of western Europe from Switzerland to the Netherlands; the Congo in central Africa; Russia’s Ob, frozen for about 200 days a year; and the Murray in Australia.
Basins seen on the model
The model below cannot hold the Amazon, but the rules are the same at every size. Switch on Basins and compare the coloured areas. The largest basin collects the most rain and feeds the thickest river. On the mountain range, the long gentle west side gathers more land into each river than the short steep east side, so the western rivers are larger, which is the same pattern you will meet in the last unit on Korea.
Drag to turn. Scroll or pinch to zoom.
| Nile | Longest river, 6,650 km (Factbook) |
| Amazon | Largest basin, about 20% of river water |
| Mississippi | Third largest basin, 2,350 miles long |
| Yangtze | Longest river in Asia |
| Mekong | Longest river in Southeast Asia |
| Ob | Frozen about 200 days a year |
- "Biggest river" can mean longest, largest basin or most water.
- The Nile is longest in the Factbook; the Amazon has the largest basin and the most water.
- River lengths differ between surveys because sources and mouths are hard to fix.
- Shared rivers need shared decisions about dams and water.
- Which river has the largest drainage basin?
- Amazon
- Nile
- Mississippi
- About what percent of the world’s river water does the Amazon carry?
- How many km longer is the Nile than the Amazon in the Factbook figures?
- The Mississippi is 2,350 miles long. About how many km is that? (1 mile = 1.609 km; nearest 10 km.)
- Why do published river lengths disagree?
- Sources and mouths can be placed differently
- Rivers grow every year
- Miles and kilometres are mixed up
- Which river carved the Grand Canyon?
- Colorado
- Rhine
- Mekong
- Which river is frozen about 200 days a year?
- Ob
- Congo
- Murray
- Which pair of rivers formed the Fertile Crescent?
- Tigris and Euphrates
- Indus and Ganges
- Rhine and Danube
- Rivers hold about 0.0002 percent of Earth’s water. How many litres is that out of every 1,000,000 litres?
- In the mountain-range model, why are the west-side rivers larger?
- Each gathers water from more land
- It rains only in the west
- The east has no rivers
Sources for this course (24)
- USGS Water Science School, Watersheds and Drainage Basins (usgs.gov/water-science-school/science/watersheds-and-drainage-basins: common outlet, drainage divide, watershed = drainage basin = catchment, larger watersheds contain smaller ones)
- USGS Nonindigenous Aquatic Species, Hydrologic Unit Codes explained (nas.er.usgs.gov/hucs.aspx: 22 regions, 245 subregions, 405 basins, about 2,400 subbasins, 19,000 watersheds, 105,000 subwatersheds)
- US Army Corps of Engineers New Orleans District, The Mississippi Drainage Basin (mvn.usace.army.mil: third largest basin after the Amazon and Congo, 41 percent of the 48 contiguous states, more than 1,245,000 square miles, 31 states and two Canadian provinces)
- US EPA, The Mississippi/Atchafalaya River Basin (epa.gov/ms-htf: 2,350 miles, 15 percent of North America, borders of 10 states, nearly 30 percent of Americans live in the basin)
- National Geographic Education encyclopedia: Source (resource/source: headwaters, the tributary farthest from the end; Gangotri Glacier, Breg spring for the Danube, Lake Itasca for the Mississippi)
- Oxbow Lake (resource/oxbow-lake: concave banks erode, convex banks collect sediment, Mississippi meander cut-offs, billabong)
- Delta (resource/delta: name from the Greek capital letter delta)
- River (resource/river)
- Anatomy of the Nile (resource/anatomy-nile: White Nile from Lake Victoria, Blue Nile from Lake Tana, Nile fan about 70,000 km2)
- Fold Mountain (resource/fold-mountain: anticline and syncline; Appalachians once taller than the Himalayas)
- USGS This Dynamic Earth, The Himalayas: Two continents collide (pubs.usgs.gov/gip/dynamic/himalaya.html: 2,900 km, collision 40 to 50 million years ago, India 6,400 km south of Asia 80 million years ago moving about 9 m a century, rising more than 1 cm a year)
- Geological Society of London, Continental/Continental: The Himalayas (crust about 75 km thick)
- Kathmandu Post, 8 Dec 2020 (Everest 8,848.86 m announced jointly by Nepal and China; Peak XV given as 8,778 m in 1847)
- 국토지리정보원 대한민국 국가지도집 청소년판 2022 (nationalatlas.ngii.go.kr): 산 (page_3151: K2 8,611 m, 안나푸르나 8,091 m, 안데스 가장 긴 산맥, 국토 약 70% 산지, 백두산 2,744 m 천지 직경 3,550 m, 한라산 1,947 m, 오름 약 370여 개)
- 강 (page_3152: 강물은 지구 물의 0.0002%, 아마존 전 세계 강물의 20%, 오비강 약 200일 결빙, 압록강 한반도에서 가장 길고 유역이 넓음)
- 산지 지형 (page_3175: 평균 고도 약 448 m, 동아시아 910 m, 백두대간과 산경표, 분수계)
- 산지 지형 also: 한라산 식생의 수직적 분포 (page_3151)
- 고위 평탄면 대관령 고랭지 채소·목축 (page_3175)
- 하천 지형 (page_3176: 동해 쪽 하천 짧고 급함, 남한에서 유역 가장 넓은 강 한강, 가장 긴 강 낙동강, 하상계수 섬진강 270, 나일강 30, 댐 이전 한강 390)
- 국가지도집 하천 (page_180: 한강 494.4 km, 유역 25,953 km2, 북한 포함 35,770 km2; 낙동강 510.3 km, 23,384 km2; 금강 397.8 km, 9,912 km2)
- 한국민족문화대백과사전 압록강 (encykorea.aks.ac.kr E0035176: 803.3 km, basin 31,226 km2)
- 낙동강 (E0011565: 521.5 km)
- 지리산 국립공원 (E0054158: 천왕봉 1,915 m)
- 국가지도집 통계 26p 주요 강의 길이 (압록강 803 km).
Checked: 2026-10-18