- This article is about the River Thames in southern England. For other meanings of the word Thames, see Thames (disambiguation)
The Thames (pronounced /temz/) is a river flowing through southern England and connecting London with the sea. The discrepancy between the spelling and the pronunciation is due to the Renaissance belief that the name comes from Greek, according to which the spelling was changed from the original Temese.
The Thames has a length of 346 kilometres (215 miles). Its source is about a mile north of the village of Kemble, near Cirencester in the Cotswolds; it then flows through Oxford (where it is called the Isis, a truncation of Tamesis, its Latin name), Wallingford, Reading, Henley-on-Thames, Marlow, Maidenhead, Eton and Windsor and London.
The Thames rises in Gloucestershire, traditionally forming the county boundary, firstly between Gloucestershire and Wiltshire, between Berkshire on the south bank and Oxfordshire on the north, between Berkshire and Buckinghamshire, between Berkshire and Surrey, between Surrey and Middlesex, and between Essex and Kent. Before the 1974 boundary changes, the boundary formed between Berkshire and Surrey was a boundary between Buckinghamshire and Surrey. The Thames is still used as an administrative border, though less so than it has been.
From the outskirts of Greater London, it passes Syon House, Hampton Court, and Richmond (with the famous view of the Thames from Richmond Hill), and Kew, before it passes through London proper, then Greenwich and Dartford and entering the sea in a drowned estuary, The Nore . Part of the area west of London is sometimes termed the Thames Valley whilst east of Tower Bridge development agencies and Ministers have taken to using the term Thames Gateway.
The river's catchment area may be divided between the non-tidal and tidal (see below) sections:
- The non-tidal section:
- Here there are an innumerable number of brooks, streams and rivers within an area of 9948.18 square kilometres (3841 square miles) and which culminates in 38 main tributaries feeding the River between its source and Teddington. These include the rivers Churn, Leach, Cole, Coln, Windrush , Evenlode , Cherwell, Ock , Thame, Pang, Kennet, Loddon, Colne, Wey and Mole.
- More than half the rain that falls on this catchment is lost to evaporation and plant growth. The remainder provides the water resource that has to be shared between river flows, to support the natural environment, and the community needs for water supplies to homes, industry and agriculture.
- The tidal section
- About 90 kilometres from the sea, at Teddington, the river begins to exhibit tidal activity from the North Sea. London was reputedly made capital of Roman Britain at the spot where the tides reached in AD 43, but this spot has moved up river in the 2000 years since then. At London, the water is slightly brackish with sea salt. Below Teddington, the principal tributaries include the rivers Brent, Wandle, Effra, Westbourne, Fleet, Ravensbourne (the final part of which is called Deptford Creek), Lea, Darent and Ingrebourne.
The whole of the River Thames drains a catchment area of some 12935 square kilometres (4994 square miles) (or 15343 square kilometres (5924 square miles) if the River Medway is included as a tributary of the River Thames).
The information relating to the catchment area has been taken from the website Floating Down the River
Between Maidenhead and Windsor, the Thames supports an artificial secondary channel, known as the Jubilee River, for flood relief purposes.
See Rivers of Great Britain for a full list of tributaries.
From over 600,000 years ago, during the Pleistocene ice age, until the Anglian glaciation around 475,000 years ago, the early River Thames flowed from Wales to Clacton-on-Sea, crossed what is now the North Sea to become a tributary of the Rhine. The river followed a path through Buckinghamshire, the southern part of Hertfordshire and Essex, running from the area of modern Staines up the valley of the Colne to Hatfield and then eastward across Essex towards the primeval Rhine. It was later diverted by encroaching ice down the valley of the modern River Lea to its present estuary position. This path was then itself blocked by a mass of ice near Hatfield and a lake ponded up to the west of this around St Albans. Waters eventually overflowed near Staines to cut the path of the modern Thames through central London. When the ice retreated about 400,000 years ago the river bed along the new route followed the lower path and so the river remained on its present day course. The flow in the Colne valley then reversed, now flowing south as a tributary into the modern Thames. Superficial gravel deposits from the primordial Thames are found throughout the Vale of St. Albans.
Numerous iron age hoards found in the lower Thames indicate the religious importance of the river. The skulls found near Hammersmith have been interpreted both as human sacrifices and as victims of Boudicca's revolt. Within the human timescale, following the example of the local Celts, the Romans called the river Tamesis: Caesar (De Bello Gallica), Cassius Dio (xl. 3) and Tacitus (Annals xiv. 32).
Richard Coates has recently suggested that the river was called the Thames upriver where it was narrower, and Plowonida down river where it was too wide to ford. This gave the name to a settlement on its banks, which became known as Londinium from the original root Plowonida derived from pre-celtic Old European 'plew' and 'nejd,' meaning something like the flowing river or the wide flowing unfordable river. See 
The Thames provided the major highway between London and Westminster in the 16th and 17th centuries. The clannish guild of watermen ferried Londoners from landing to landing, and tolerated no outside interference. A versifying waterman, John Taylor, the Water Poet (1580—1654), described the river in a poem commemorating a voyage from Oxford to London,
In the 17th and 18th centuries, during the period now referred to as the Little Ice Age, the Thames often froze over in the winter. This led to the first Frost Fair in 1607, complete with a tent city set up on the river itself and offering a number of amusements, including ice bowling. After temperatures began to rise again, starting in 1814, the river never again froze over completely. The building of a new London Bridge in 1825 may also have been a factor; the new bridge had fewer pillars than the old and so allowed the river to flow more freely, thus preventing it from flowing slowly enough to freeze in cold winters.
By the 18th century, the Thames was one of the world's busiest waterways, as London became the centre of the vast, mercantile British Empire. During this time one of the worst river disasters in England took place on September 3, 1878 on the Thames, when the crowded pleasure boat Princess Alice collided with the Bywell Castle killing over 640.
In the 'Great Stink' of 1858, pollution in the river became so bad that sittings at the House of Commons at Westminster had to be abandoned. A concerted effort to contain the city's sewage by constructing massive sewers on the north and south river embankments followed, under the supervision of engineer Joseph Bazalgette.
The coming of rail and road transportation, and the decline of the Empire in the years following 1914, have reduced the prominence of the river. London itself is no longer a port of any note, and the Port of London has moved downstream to Tilbury. In return, the Thames has undergone a massive clean-up from the filthy days of the late 19th and early- to mid-20th centuries, and life has returned to its formerly dead waters. It is now the cleanest river in the world which flows through a city.
In the early 1980s, a massive flood control device, the Thames Barrier, was opened. It is closed several times a year to prevent water damage to London's low lying areas upstream. In the late 1990s, the 12km long Jubilee River was built, which acts as a flood channel for a section of the Thames around Maidenhead and Windsor. 
Many books refer to the Thames. Three Men in a Boat by Jerome K. Jerome describes a boat trip up the Thames. Somewhere near the Oxford stretch is where the Liddells were rowing in the poem at the start of Alice's Adventures in Wonderland. The river is mentioned in both The Wind in the Willows and the play Toad of Toad Hall.
In books set in London there is Sherlock Holmes looking for a boat in A Study in Scarlet; in Oliver Twist, Bill Sikes kills Nancy just near the river.
The Thames also features prominently in Philip Pullman's His Dark Materials trilogy, as a communications artery for the waterborne 'Gyptian people of Oxford and the Fens.
In poetry, T.S. Eliot references the Thames at the beginning of The Fire Sermon, Section III of "The Wasteland".
Two important events in the English sporting calandar occur on the River Thames. The University Boat Race is rowed between the University of Oxford and the University of Cambridge on the tidal portion of the river from Putney to Mortlake in the west of London. The Henley Royal Regatta is another rowing event which takes place over a number of days at the upstream town of Henley-on-Thames; besides its sporting significance the regatta is an important date on the English social calendar alongside Royal Ascot and Wimbledon.
The River Thames is navigable from the estuary as far as Halfpenny Bridge at Lechlade. Between the sea and Teddington Lock, the river forms part of the Port of London and navigation is administered by the Port of London Authority. From Teddington Lock to the head of navigation, the navigation authority is the Environment Agency.
The river is navigable to large ocean going ships as far as the Pool of London and London Bridge. Today little commercial traffic passes above the docks at Tilbury, and central London sees only the occasional visiting cruise ship or warship moored alongside HMS Belfast and a few smaller aggregate or refuse carrying vessels operating from wharves in the west of London. Both the tidal river through London, and the non-tidal river upstream, are intensively used for leisure navigation.
There are 45 locks on the River Thames. See Locks on the River Thames for a full list of all locks.
The River Thames is crossed by many bridges and tunnels. Famous crossings of the Thames include:
See Crossings of the River Thames for a full list of all crossings.
Famous islands in the Thames include:
See Islands in the River Thames for a full list of all islands.
- Richard Bradley /K. Gordon, Human skulls from the river Thames, their dating and significance. Antiquity 62, 1988, 503 ff.