River Thames
Longest river entirely in England, flowing through London.
The River Thames flows through southern England including London. At 215 miles (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.
- Length
- 215 miles (346 km)
- Source
- Thames Head, Gloucestershire
- Mouth
- North Sea near Tilbury, Essex and Gravesend, Kent
- Discharge
- Low considering its length and breadth; the Severn has a discharge almost twice
- Navigation locks
- 45
- Named tributaries
- At least 50
- Islands
- Over 80
Lore & Background
The river's name, from Middle English Temese, is derived from the Brittonic name Tamesas, recorded in Latin as Tamesis. The name element Tam may have meant 'dark', with cognates in Slavic, Lithuanian, Sanskrit, and Welsh. Kenneth H. Jackson proposed that the name is not Indo-European, while Peter Kitson suggested it is Indo-European, indicating 'muddiness' from a root *tā-, 'melt'. Early variants include Tamesa, Tamesis, Tamis, Temes, Tamise, and Thamis. Indirect evidence for the antiquity of the name is provided by a Roman potsherd found at Oxford, bearing the inscription Tamesubugus fecit. 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', is found in Magna Carta. The Thames through Oxford is sometimes called the Isis. Historically, gazetteers and cartographers insisted that the entire river was correctly named the Isis from its source down to Dorchester on Thames, where it meets the Thame and becomes the 'Thame-isis'. Ordnance Survey maps still label the Thames as 'River Thames or Isis' down to Dorchester. 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 are located on the bridge at Henley-on-Thames, Oxfordshire.
Reader's Guide
The River Thames is a major maritime route for shipping and supplies, through the Port of London for international trade and via connections to the British canal system. Its position has placed 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 rivers: the Kennet and Avon Canal (Reading to Bath) and the Grand Union Canal (London to the Midlands). The river supports rowing, sailing, kayaking, and canoeing, with major annual events including the Henley Royal Regatta and the Boat Race. It was used during two Summer Olympic Games: 1908 (rowing) and 1948 (rowing and canoeing). The river's name is used in those of Thames Valley Police, Thames Water, Thames Television, publishing company Thames & Hudson, Thameslink, and South Thames College. Marks of human activity dating back to Pre-Roman Britain are visible along the river, including navigations, bridges, watermills, and 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. Along its course are 45 navigation locks with accompanying weirs. The river contains over 80 islands.
Did You Know?
- The river's 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 (180 ft).
- In Scotland, the Tay achieves more than double the Thames' average discharge from a drainage basin that is 60% smaller.
- The lower reaches of the river are called the Tideway, derived from its long tidal reach up to Teddington Lock.
- The river contains over 80 islands.
Frequently Asked Questions
Who is River Thames?
The River Thames is a major waterway threading through southern England, most recognizably passing through the heart of London. At 215 miles (346 km), it holds the title of the longest river lying entirely within England.
What are River Thames's key features and role?
The Thames functions as a busy navigable route equipped with 45 navigation locks and fed by at least 50 named tributaries. Despite its considerable length and breadth, its average discharge is notably modest, with the Severn carrying roughly twice the flow.
Where does River Thames begin and where does its story end?
The river takes its source at Thames Head in Gloucestershire and eventually pours into the North Sea via the Thames Estuary near Tilbury, Essex, and Gravesend, Kent.
Why is River Thames important to the UK?
As the longest river wholly contained in England, the Thames has shaped the region's trade, settlement patterns, and cultural identity for centuries. Its course through London cements its status as one of the most iconic waterways in the country.
How does River Thames compare to the River Severn?
The Severn is longer overall and carries nearly double the average discharge, which is why it claims the top spot in the UK. The Thames, however, retains the distinction of being the longest river that stays entirely within England's borders.
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