50 free River Thames trivia questions with answers — geography quiz, new questions added Aug 2026.
The Thames is only 215 miles long and carries less water than the Severn or the Tay, but no river in Britain has been written about, painted, fought over, frozen, poisoned and cleaned up quite so thoroughly. This quiz starts with the geography a beginner can manage (where it rises, where it meets the sea, what the Oxford stretch is called, where the tide stops) and works up to the Anglian ice sheet that pushed the river onto its London course, the Nore lightship, the 45 locks and 80-plus islands, and the seals, seahorses and stray whales that turn up in it today. It then follows the river through history: Caesar's crossing, Londinium's founding, Magna Carta at Runnymede, the frost fairs and the elephant on the ice, the open sewer of the 1300s, the Great Stink of 1858 and Joseph Bazalgette's cure, the Princess Alice disaster, Marc Brunel's tunnel, Tower Bridge, the 1928 flood and the Thames Barrier, and the £5 billion super-sewer finished in 2025. Rowing, swimming and the arts get their turn too: the Boat Race, Doggett's Coat and Badge, Handel's Water Music, Three Men in a Boat, The Wind in the Willows and Waterloo Sunset. Every answer was checked against Wikipedia's articles on the River Thames and its landmarks, and each question shows the sentence that supports it. Try our London, England and rivers quizzes next.
30 of 50 questions with answers and explanations. Play the quiz
Q 01How long is the River Thames?
215 miles
That makes it the longest river entirely in England, though the Severn, which starts in Wales, is longer overall.
Q 02What is the Thames called as it passes through the city with the university boat clubs and Folly Bridge?
The Isis
Victorian mapmakers insisted the whole river was the Isis down to Dorchester, where it meets the Thame; Ordnance Survey maps still label it 'River Thames or Isis' there.
Q 03The usually quoted source of the Thames, Thames Head, is in which county?
Gloucestershire
It lies near Kemble in the Cotswolds and is a winterbourne, flowing only seasonally.
Q 04The rival source at Seven Springs would add 14 miles to the Thames and make it longer than which river?
Severn
Measured from Seven Springs the Churn/Thames runs 229 miles against the Severn's 220.
Q 05Into which sea does the Thames flow?
North Sea
It reaches the sea through the Thames Estuary near Southend-on-Sea, Tilbury and Gravesend.
Q 06The tidal stretch of the Thames is known by what name?
The Tideway
The tide runs up as far as Teddington Lock, with a rise and fall of about 7 metres.
Q 07Which lock marks the normal tidal limit of the Thames?
Teddington
Before the lock was built in 1810-12, spring tides reached as far up as Staines.
Q 08How many navigation locks are there on the non-tidal Thames?
45
Each comes with a weir; the Environment Agency staffs them for most of the day and enforces an 8 km/h speed limit.
Q 09The Thames contains roughly how many islands?
Over 80
They range from the marshy Isle of Sheppey and Canvey Island to tiny eyots; Parliament stands on the former Thorney Island.
Q 10What share of London's drinking water comes from the Thames itself?
Two-thirds
The basin is among the driest parts of the UK, so the river's flow is low for its size and heavily abstracted.
Q 11The Brittonic root 'Tam' in the river's name is thought to have meant what?
Dark
The same root shows up in the Tamar, Tame, Tavy, Teme and Teviot.
Q 12Which politician coined the phrase 'The Thames is liquid history' in 1929?
John Burns
The one-time MP for Battersea was answering an American who had compared it unfavourably with the Mississippi.
Q 13About 450,000 years ago, which ice age diverted the Thames onto its present course through London?
Anglian
Before that the river ran north-east through Hertfordshire and East Anglia to reach the sea near Ipswich.
Q 21Which king described the Thames in 1357 as full of 'dung and other filth' and 'abominable stenches'?
Edward III
The river had been used as London's open sewer since at least the 1300s; a public lavatory on London Bridge emptied straight into it.
Q 22The first Frost Fair, with a tent city and ice bowling on the frozen Thames, was held in which year?
1607
The old multi-piered London Bridge slowed the flow and made freezing more likely; the last fair, in 1814, saw an elephant led across the ice.
Q 23What was led across the frozen Thames below Blackfriars during the last frost fair of 1814?
An elephant
The fair lasted four days between Blackfriars and London Bridge; the new bridge of 1825 let the river flow freely and it never froze over again.
Q 14What is the sandbank at the mouth of the Thames Estuary that got the world's first lightship in 1732?
The Nore
It marked the seaward limit of the Port of London until 1964 and is now marked by Sea Reach No. 1 Buoy.
Q 15The annual tradition of counting the Thames's swans is called what?
Swan Upping
Mute swans are the familiar residents; escaped black swans are rarer.
Q 16Roughly how many grey and harbour seals live in the Thames Estuary?
Up to 700
Seals have been spotted as far upriver as Richmond, and dolphins and porpoises also visit.
Q 17In January 2006 a northern bottle-nosed whale swam up the Thames as far as which district?
Chelsea
It died on a barge during a rescue attempt; a beluga nicknamed Benny visited Gravesend in 2018.
Q 18Which Roman leader's account of his 54 BC expedition contains some of the earliest references to the Thames?
Julius Caesar
The river was a major obstacle, defended by the Belgic Catuvellauni and Atrebates.
Q 19Londinium grew up on the north bank around which stream in about AD 47?
Walbrook
Cornhill and Ludgate Hill offered a defensible site where the river was deep enough for ships yet narrow enough to bridge.
Q 20King John was forced to grant Magna Carta in 1215 beside the Thames at which meadow?
Runnymede
Clause 23 of the charter granted the barons the right of navigation on the river.
Q 24Doggett's Coat and Badge, one of the oldest sporting events in the world, is a rowing race for whom?
Apprentice watermen
Thomas Doggett founded it in 1715 out of gratitude to a waterman who rowed him home against the tide.
Q 25Stone from which hills was floated down the Thames from Radcot to rebuild St Paul's Cathedral after 1666?
Cotswolds
Barges from Oxford also carried timber, wool, food and livestock daily to London.
Q 26The people who scavenged in the Thames mud for a living in the 18th and 19th centuries were called what?
Mudlarks
Household cesspools overflowed into the streets and sewers and ended up in the river.
Q 27What was the 'Great Stink' of 1858?
River pollution so bad Parliament had to abandon sittings
Chlorine-soaked drapes were hung in the Commons' windows to no effect.
Q 28Which engineer built the massive embankment sewers that cleaned up the Victorian Thames?
Joseph Bazalgette
Four cholera outbreaks had killed tens of thousands between 1832 and 1865, and Prince Albert's 1861 death is often blamed on typhoid from the river at Windsor.
Q 29The 1878 collision of the pleasure boat Princess Alice with the Bywell Castle killed how many people?
Over 640
It remains one of the worst river disasters in England.
Q 30Marc Brunel's 1843 passage beneath the Thames was the world's earliest of what kind?
Underwater tunnel
It now carries the East London Line; the Tower Subway was the first railway under the river.