50 free Mekong River trivia questions with answers — geography quiz, new questions added Aug 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 50 questions with answers and explanations. Play the quiz
Q 01How many countries does the Mekong flow through?
6
China, Myanmar, Laos, Thailand, Cambodia and Vietnam.
Q 02What is the Mekong officially called in China?
Lancang
The name comes from the Lao kingdom of Lan Xang, though the characters can be read as turbulent green river.
Q 03On which high plateau does the Mekong rise?
The Tibetan
Its headwaters are protected in the Sanjiangyuan reserve, alongside those of the Yellow River and Yangtze.
Q 04What is the estimated length of the Mekong?
4,909 km
Its drainage basin covers about 795,000 square kilometres.
Q 05Where does the Mekong rank among the world's longest rivers?
Twelfth
It is the third-longest in Asia.
Q 06What does 'Mae Nam', the Thai and Lao prefix in the river's original name, mean?
Mother of Waters
Khong itself is an archaic loanword meaning river, related to the Chinese jiang.
Q 07What does the Vietnamese name Sông Cửu Long, used for the Mekong in its delta, mean?
Nine Dragons River
The delta splits into many distributaries, including the Tiền, Bassac and Hàm Luông.
Q 08Which two other great rivers run parallel to the Mekong through the gorges of Yunnan?
Yangtze and Salween
The Three Parallel Rivers area lies in the Hengduan Mountains.
Q 09Which three countries meet at the Golden Triangle tripoint where the Ruak joins the Mekong?
Myanmar, Laos and Thailand
The wider region of the three countries was notorious for opium production.
Q 10Who coined the term 'Golden Triangle' in 1971?
A US State Department official
Marshall Green used it at a press conference on the opium trade.
Q 11What does the name of the Khon Pi Long rapids on the Lao border mean?
Where the ghost lost its way
They divide Chiang Rai in Thailand from Bokeo province in Laos.
Q 12Roughly how long is the Mekong's first stretch of Laos's western border, tripoint to Khong Chiam?
920 km
It later marks the same border again for another 850 km.
Q 13Which capital city stands on the Mekong at its junction with the Tonlé Sap?
Phnom Penh
The river's main distributary branches off just south of the city, beginning the delta.
Q 21The Khone Falls area is known as Si Phan Don, meaning what?
The four thousand islands
The falls are the main reason the Mekong cannot be navigated into China.
Q 22What did French colonists build after failing to get boats past the Khone Falls?
A railway across two islands
The Don Det-Don Khon railway carried cargo around the cataracts.
Q 23Who was the first European to encounter the Mekong, in 1540?
António de Faria
A European map of 1563 shows the river, though little was known upstream of the delta.
Q 14What unusual thing happens to the Tonlé Sap river when the Mekong floods?
Its flow reverses
Floodwaters push back up into the Great Lake, then drain out again in the dry season.
Q 15Tonlé Sap holds what distinction in Southeast Asia?
Largest freshwater lake
UNESCO made it a Biosphere Reserve in 1997.
Q 16Tonlé Sap's post-monsoon water level can be how far above its dry-season level?
Up to 10 metres
Its area swells from around 2,500 square kilometres in the dry season.
Q 17What is the first and main distributary that branches off the Mekong south of the Cambodian capital?
Bassac River
Its branching marks the beginning of the Mekong Delta.
Q 18Roughly what share of Vietnam's agricultural land lies in the Mekong Delta?
A quarter
About 2.6 million hectares of the delta are farmed.
Q 19Which Mekong Delta city's research institute predicts a key road will be flooded 365 days a year by 2050?
Cần Thơ
Sea-level rise and land subsidence combine to threaten the low-lying delta.
Q 20Where do the Khone Falls, the widest waterfall in the world, lie?
Southern Laos
They stretch 10,783 metres across in Champasak Province, near the Cambodian border.
Q 24Which nation's trader Gerrit van Wuysthoff led an expedition up the Mekong to Vientiane in 1641-42?
Dutch
European interest remained sporadic until the French arrived in the 19th century.
Q 25What was the chief finding of the French Mekong Expedition of 1866-68?
That its falls and rapids ruled out navigation
Ernest Doudard de Lagrée and Francis Garnier led it from the mouth to Yunnan.
Q 26Which Russian explorer found the source of the Mekong in 1900?
Pyotr Kozlov
The French had extended their control into Laos from 1893.
Q 27What was found in excavations at Oc Eo, in the ancient Funan culture of the delta?
Roman coins
Funan, of the 1st century, was the earliest recorded civilisation on the river.
Q 28Which four countries founded the Mekong River Commission in 1995?
Laos, Thailand, Cambodia, Vietnam
China and Myanmar joined as dialogue partners the following year.
Q 29Only which river basin has higher biodiversity than the Mekong's?
The Amazon
Estimates count around 850 freshwater fish species and 20,000 plants in the Greater Mekong.
Q 30On average, how often were new species discovered in the Mekong region between 1997 and 2015?
Two a week
In 2009 alone, 145 species new to science were described there.