Mekong River Trivia
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38 free Mekong River trivia questions with answers — geography quiz, new questions added Sep 2026.
This Mekong trivia quiz follows the river from the Tibetan Plateau to the South China Sea. The easy questions are the ones any geography student can manage: which countries it flows through, where it rises, what China calls it, and which capital city sits at its great confluence. From there it moves into the physical river: its length and rank among the world's rivers, the Golden Triangle tripoint, the rapids and the widest waterfall on Earth, and the lake in Cambodia whose river reverses direction every year. The harder end is for people who know the region: the Kra-Dai origin of the name, the first European to reach the river in 1540, the French expedition that proved it could never be navigated to China, the Russian who found the source in 1900, the record-breaking giant stingray and giant catfish, the Irrawaddy dolphins, the number of new species found each week, the Mekong River Commission, the first Thai-Lao Friendship Bridge and the controversial Xayaburi Dam. It also covers the delta's rice, the Nine Dragons name and the delta's vulnerability to rising seas. Every answer was checked against encyclopaedia entries on the Mekong, its delta, Tonlé Sap, its wildlife and its dams before publishing, and the supporting sentence is stored with each question. If you enjoy this one, try our Vietnam, Cambodia, Thailand and world rivers quizzes next.
30 of 38 questions with answers and explanations. Play the quiz
Q 01Into which sea does the Mekong empty through its delta, after crossing six countries?
The South China Sea
The South China Sea receives it; illegal sand mining in the delta has deepened the riverbed and let seawater push farther inland.
Q 02What is the Mekong officially called in China?
Lancang
Lancang is its official name in China, where a cascade of large dams now holds back the upper river.
Q 03On which high plateau does the Mekong rise?
The Tibetan
The Tibetan Plateau is where it rises, and snowmelt from those heights supplies a big share of the lower river's flow in the dry season.
Q 04Which Mekong catfish, farmed in Vietnam and exported worldwide, is sold in US stores as swai?
Pangasius
Pangasius is sold cheaply as swai in the US and as panga in Europe, where its low price and mild taste made it a supermarket staple.
Q 05Which glowing lights are said to rise from the Mekong each October, at the end of the Buddhist rains retreat?
Naga fireballs
Naga fireballs are credited to the river serpent Naga; scientists have suggested flammable phosphine gas from the marshes, but no explanation has held up.
Q 06What does 'Mae Nam', the Thai and Lao prefix in the river's original name, mean?
Mother of Waters
Mother of Waters is the meaning, and because Khong itself meant 'river', the name Mekong says 'river' twice over.
Q 07What does the Vietnamese name Sông Cửu Long, used for the Mekong in its delta, mean?
Nine Dragons River
Nine Dragons River refers to the nine mouths through which the delta's branches reach the sea.
Q 08Which two other great rivers run parallel to the Mekong through the gorges of Yunnan?
Yangtze and Salween
Yangtze and Salween run beside it for over 300 km, then part so widely that the Salween meets the Indian Ocean and the Yangtze reaches the sea at Shanghai.
Q 09Which three countries meet at the Golden Triangle tripoint where the Ruak joins the Mekong?
Myanmar, Laos and Thailand
Myanmar, Laos and Thailand meet here, though the Golden Triangle name first covered their whole mountainous border region before tourism pinned it to this confluence.
Q 10Which former royal capital, a UNESCO World Heritage town, stands where the Nam Khan river meets the Mekong?
Luang Prabang
Luang Prabang lost its crown when King Setthathirath moved the royal capital downriver to Vientiane, fearing Burmese attacks.
Q 11Which animal, first seen by scientists for sale as meat in a Mekong town market, turned out to be a living fossil?
Rock rat
Rock rat was the find: its family, the Diatomyidae, had been thought extinct for about 11 million years.
Q 12Which capital city stands on the Mekong at its junction with the Tonlé Sap?
Phnom Penh
Phnom Penh means 'Penh's hill', after a rich widow who, legend says, built a hilltop temple there to house Buddha statues.
Q 13What unusual thing happens to the Tonlé Sap river when the Mekong floods?
Its flow reverses
Its flow reverses each year, filling the great lake, and Cambodia's Water Festival boat races are held when the river turns back.
Q 21What did French colonists build after failing to get boats past the Khone Falls?
A railway across two islands
A railway across two islands let the French take specially built boats apart, haul the pieces on wagons and relaunch them upstream.
Q 22The first European known to have encountered the Mekong, in 1540, came from which country?
Portugal
Portugal's António de Faria saw it first, yet even a European map of 1563 showed little of the river beyond its delta.
Q 23Which European nation's traders took a boat expedition up the Mekong as far as Vientiane in 1641?
Dutch
Dutch trader Gerrit van Wuysthoff was received with honours, but his boats had to be unloaded and carried past waterfalls, so no trading post followed.
Q 14The ruins of which ancient Khmer capital lie just north of the Tonlé Sap, Southeast Asia's largest lake?
Angkor
Angkor was sacked by the kingdom of Ayutthaya around 1431, and its most treasured artworks were carried off to the victors' capital.
Q 15Fa Ngum's Lao kingdom on the Mekong was named for a million of which animal?
Elephants
Elephants: the name alluded to the king's military might, above all his army's countless war elephants.
Q 16Which river is the first and main distributary to branch off the Mekong, beginning its delta?
Bassac River
Bassac River: from Châu Đốc on its bank, Emperor Gia Long ordered the Vĩnh Tế Canal dug along the Cambodian border to guard the frontier.
Q 17In which Marguerite Duras novel does a French schoolgirl meet a wealthy Chinese man on a Mekong ferry?
The Lover
The Lover drew on Duras's own teenage affair; after clashing with the director adapting it for film, she rewrote the story as a new book.
Q 18Which city, the Mekong Delta region's seat and economic centre, is famed for its floating markets?
Cần Thơ
Cần Thơ got a cable-stayed bridge in 2010 that replaced the ferries carrying National Route 1 across the river.
Q 19Where do the Khone Falls, the widest waterfall in the world, lie?
Southern Laos
Southern Laos is where they block boat traffic between Cambodia and China, defeating repeated French attempts to take steamers upriver.
Q 20The Khone Falls area is known as Si Phan Don, meaning what?
The four thousand islands
The four thousand islands lie so low that many of them disappear underwater when the Mekong is in flood.
Q 24Vat Phou, the ruined Khmer temple on a mountainside near the Mekong in Champasak, was built for which Hindu god?
Shiva
Shiva was believed to dwell on the mountain because its peak has a natural linga shape, and the ruins later became a Buddhist pilgrimage site.
Q 25Which future US Secretary of State commanded a Swift boat in the Mekong Delta during the Vietnam War?
John Kerry
John Kerry commanded Swift boats there, and when veterans disputed his war record in 2004, 'swiftboating' became a byword for an unfair political attack.
Q 26What was found in excavations at Oc Eo, in the ancient Funan culture of the delta?
Roman coins
Roman coins, or local copies, turned up there, including one of Antoninus Pius worn as a pendant; the port may be the Cattigara known to Roman merchants.
Q 27Which four countries founded the Mekong River Commission in 1995?
Laos, Thailand, Cambodia, Vietnam
Laos, Thailand, Cambodia, Vietnam signed it, bringing back Cambodia, which had left the older Mekong Committee while the Khmer Rouge ruled.
Q 28Which river basin is the only one with greater biodiversity than the Mekong's?
The Amazon
The Amazon is the only richer basin, yet as dams have gone up on the river, fishers have been landing smaller and fewer fish.
Q 29On average, how often were new species discovered in the Mekong region between 1997 and 2015?
Two a week
Two a week on average, even as poachers killed Vietnam's last Javan rhino in 2010.
Q 30Which fish, caught in the Mekong in 2022, is the largest strictly freshwater fish ever documented?
A 300 kg giant stingray
A 300 kg giant stingray, nearly 4 m long, was documented, tagged and released; sturgeon grow bigger but spend part of their lives at sea.