"Thames" and "Tamesis" redirect here. For other uses of "Thames", see

THAMES RIVER
"Thames" and "Tamesis" redirect here. For other uses of "Thames", see Thames (disambiguation). For the town in Colombia, see Támesis, Antioquia. For the publisher, see Tamesis Books.
The River Thames known alternatively in parts as the River Isis, is a river that flows through southern England, including London. At 215 mi (346 km), it is the longest river entirely in England and the second-longest in the United Kingdom, after the River Severn.
The river rises at Thames Head in Gloucestershire, and flows into the North Sea near Tilbury, Essex and Gravesend, Kent, via the Thames Estuary. From the west it flows through Oxford (where it is sometimes called the Isis), Reading, Henley-on-Thames and Windsor. The Thames also drains the whole of Greater London.^[1]
The lower reaches of the river are called the Tideway, derived from its long tidal reach up to Teddington Lock. Its tidal section includes most of its London stretch and has a rise and fall of 23 ft (7 m). From Oxford to the Estuary the Thames drops by 55 metres. Running through some of the drier parts of mainland Britain and heavily abstracted for drinking water, the Thames' discharge is low considering its length and breadth: the Severn has a discharge almost twice as large on average despite having a smaller drainage basin. In Scotland, the Tay achieves more than double the Thames' average discharge from a drainage basin that is 60% smaller.
Along its course are 45 navigation locks with accompanying weirs. Its catchment area covers a large part of south-eastern and a small part of western England; the river is fed by at least 50 named tributaries. The river contains over 80 islands. With its waters varying from freshwater to almost seawater, the Thames supports a variety of wildlife and has a number of adjoining Sites of Special Scientific Interest, with the largest being in the North Kent Marshes and covering 5,289 ha (20.4 sq mi).
A statue of Old Father Thames by Raffaelle Monti at St John's Lock, Lechlade
According to Mallory and Adams, the Thames, from Middle English Temese, is derived from the Brittonic name for the river, Tamesas (from *tamēssa),^[3] recorded in Latin as Tamesis and yielding modern Welsh Tafwys "Thames". The name may have meant "dark" and can be compared to other cognates such as Russian темно (Proto-Slavic *tĭmĭnŭ), Lithuanian tamsi "dark", Latvian tumsa "darkness", Sanskrit tamas and Welsh tywyll "darkness" and Middle Irish teimen "dark grey".^[3] The origin is shared by many other river names in Britain, such as the River Tamar at the border of Devon and Cornwall, several rivers named Tame in the Midlands and North Yorkshire, the Tavy on Dartmoor, the Team of the North East, the Teifi and Teme of Wales, the Teviot in the Scottish Borders and a Thames tributary the Thame.
Kenneth H. Jackson proposed that the name of the Thames is not Indo-European (and of unknown meaning),^[4] while Peter Kitson suggested that it is Indo-European but originated before the Britons and has a name indicating "muddiness" from a root *tā-, 'melt'.^[5]
Indirect evidence for the antiquity of the name 'Thames' is provided by a Roman potsherd found at Oxford, bearing the inscription Tamesubugus fecit (Tamesubugus made [this]). It is believed that Tamesubugus' name was derived from that of the river.^[6] Tamese was referred to as a place, not a river in the Ravenna Cosmography (c. AD 700).
The river's name has always been pronounced with a simple t /t/; the Middle English spelling was typically Temese and the Brittonic form Tamesis. A similar spelling from 1210, "Tamisiam" (the accusative case of "Tamisia", see Kingston upon Thames#Early history), is found in the Magna Carta.^[7]
Sculpture of Tamesis. Downstream keystone of the central arch of Henley Bridge
The Thames through Oxford is sometimes called the Isis. Historically, and especially in Victorian times, gazetteers and cartographers insisted that the entire river was correctly named the Isis from its source down to Dorchester on Thames and that only from this point, where the river meets the Thame and becomes the "Thame-isis" (supposedly subsequently abbreviated to Thames) should it be so called. Ordnance Survey maps still label the Thames as "River Thames or Isis" down to Dorchester. Since the early 20th century this distinction has been lost in common usage outside of Oxford, and some historians suggest the name Isis is nothing more than a truncation of Tamesis, the Latin name for the Thames. Sculptures titled Tamesis and Isis by Anne Seymour Damer can be found on the bridge at Henley-on-Thames, Oxfordshire (the original terracotta and plaster models were exhibited at the Royal Academy, London, in 1785. They are now on show at the River and Rowing Museum in Henley).^[8]
Richard Coates suggests that while the river was as a whole called the Thames, part of it, where it was too wide to ford, was called *(p)lowonida. This gave the name to a settlement on its banks, which became known as Londinium, from the Indo-European roots *pleu- "flow" and *-nedi "river" meaning something like the flowing river or the wide flowing unfordable river.^[9][10]
The river gives its name to three informal areas: the Thames Valley, a region of England around the river between Oxford and West London; the Thames Gateway; and the greatly overlapping Thames Estuary around the tidal Thames to the east of London and including the waterway itself. Thames Valley Police is a formal body that takes its name from the river, covering three counties. In non-administrative use, the river's name is used in those of Thames Valley University, Thames Water, Thames Television, publishing company Thames & Hudson, Thameslink (north–south rail service passing through central London) and South Thames College. An example of its use in the names of historic entities is the Thames Ironworks and Shipbuilding Company.
Administration[edit]
The administrative powers of the Thames Conservancy to control river traffic and manage flows have been taken on, with some modifications by the Environment Agency and, in respect of the Tideway part of the river, such powers are split between the agency and the Port of London Authority.
Human activity[edit]
The marks of human activity, in some cases dating back to Pre-Roman Britain, are visible at various points along the river. These include a variety of structures connected with use of the river, such as navigations, bridges and watermills, as well as prehistoric burial mounds.
The lower Thames in the Roman era was a shallow waterway winding through marshes. But centuries of human intervention have transformed it into a deep tidal canal flowing between 200 miles of solid walls; these defend a floodplain where 1.5 million people work and live.
Main article: Embanking of the tidal Thames
A major maritime route is formed for much of its length for shipping and supplies: through the Port of London for international trade, internally along its length and by its connection to the British canal system. The river's position has put it at the centre of many events in British history, leading to it being described by John Burns as "liquid history".
Two broad canals link the river to other river basins: the Kennet and Avon Canal (Reading to Bath) and the Grand Union Canal (London to the Midlands). The Grand Union effectively bypassed the earlier, narrow and winding Oxford Canal which also remains open as a popular scenic recreational route. Three further cross-basin canals are disused but are in various stages of reconstruction: the Thames and Severn Canal (via Stroud), which operated until 1927 (to the west coast of England), the Wey and Arun Canal to Littlehampton, which operated until 1871 (to the south coast), and the Wilts and Berks Canal.
Rowing and sailing clubs are common along the Thames, which is navigable to such vessels. Kayaking and canoeing also take place. Major annual events include the Henley Royal Regatta and the Boat Race, while the Thames has been used during two Summer Olympic Games: 1908 (rowing) and 1948 (rowing and canoeing). Safe headwaters and reaches are a summer venue for organised swimming, which is prohibited on safety grounds in a stretch centred on Central London.
Physical and natural aspects[edit]

The marker stone at the official source of the River Thames named Thames Head near Kemble

The Seven Springs source
The Thames Barrier provides protection against floods
The Thames passes by some of the sights of London, including the Houses of Parliament and the London Eye
The Thames passing through the London Borough of Richmond upon Thames
The usually quoted source of the Thames is at Thames Head (at grid reference ST980994). This is about ³⁄₄ mi (1.2 km)^[11] north of Kemble parish church in southern Gloucestershire, near the town of Cirencester, in the Cotswolds.^[12]
However, Seven Springs near Cheltenham, where the Churn (which feeds into the Thames near Cricklade) rises, is also sometimes quoted as the Thames' source as this location is farthest from the mouth, and adds some 14 mi (23 km) to the river's length. At Seven Springs above the source is a stone with the Latin hexameter inscription "Hic tuus o Tamesine pater septemgeminus fons", which means "Here, O Father Thames, [is] your sevenfold source".
The springs at Seven Springs flow throughout the year, while those at Thames Head are only seasonal (a winterbourne). The Thames is the longest river entirely in England. (The longest river in the United Kingdom, the Severn, flows partly in Wales.) However, as the River Churn, sourced at Seven Springs, is 14 mi (23 km) longer than the section of the Thames from its traditional source at Thames Head to the confluence, the overall length of the Thames measured from Seven Springs, at 229 mi (369 km), is greater than the Severn's length of 220 mi (350 km. Thus, the "Churn/Thames" river may be regarded as the longest natural river in the United Kingdom.
The stream from Seven Springs is joined at Coberley by a longer tributary which could further increase the length of the Thames, with its source in the grounds of the National Star College at Ullenwood.
The Thames flows through or alongside Ashton Keynes, Cricklade, Lechlade, Oxford, Abingdon-on-Thames, Wallingford, Goring-on-Thames and Streatley, Pangbourne and Whitchurch-on-Thames, Reading, Wargrave, Henley-on-Thames, Marlow, Maidenhead, Windsor and Eton, Staines-upon-Thames and Egham, Chertsey, Shepperton, Weybridge, Sunbury-on-Thames, Walton-on-Thames, Molesey and Thames Ditton. The river was subject to minor redefining and widening of the main channel around Oxford, Abingdon and Marlow before 1850, since when further cuts to ease navigation have reduced distances further.
Molesey faces Hampton, and in Greater London the Thames passes Hampton Court Palace, Surbiton, Kingston upon Thames, Teddington, Twickenham, Richmond (with a famous view of the Thames from Richmond Hill), Syon House, Kew, Brentford, Chiswick, Barnes, Hammersmith, Fulham, Putney, Wandsworth, Battersea and Chelsea. In central London, the river passes Pimlico and Vauxhall, and then forms one of the principal axes of the city, from the Palace of Westminster to the Tower of London. At this point, it historically formed the southern boundary of the medieval city, with Southwark, on the opposite bank, then being part of Surrey.
Beyond central London, the river passes Bermondsey, Wapping, Shadwell, Limehouse, Rotherhithe, Millwall, Deptford, Greenwich, Cubitt Town, Blackwall, New Charlton and Silvertown, before flowing through the Thames Barrier, which protects central London from flooding by storm surges. Below the barrier, the river passes Woolwich, Thamesmead, Dagenham, Erith, Purfleet, Dartford, West Thurrock, Northfleet, Tilbury and Gravesend before entering the Thames Estuary near Southend-on-Sea.