This is a list of the longest rivers of the United Kingdom.

Longest rivers of the United Kingdom

There seems to be little consensus in published sources as to the lengths of rivers, nor much agreement as to what constitutes a river. Thus the River Ure and River Ouse can be counted as one river system or as two rivers. If it is counted as one, the

River Aire The River Aire is a major river in Yorkshire, England, in length. The ''Handbook for Leeds and Airedale'' (1890) notes that the distance from Malham to Howden is direct, but the river's meanderings extend that to . Between Malham Tarn and Ai ...

/ River Ouse/

Humber The Humber is a large tidal estuary on the east coast of Northern England. It is formed at Trent Falls, Faxfleet, by the confluence of the tidal rivers Ouse and Trent. From there to the North Sea, it forms part of the boundary between th ...

system would come fourth in the list, with a combined length of ; and the

River Trent The Trent is the Longest rivers of the United Kingdom, third-longest river in the United Kingdom. Its Source (river or stream), source is in Staffordshire, on the southern edge of Biddulph Moor. It flows through and drains the North Midland ...

/Humber system would top the list with their combined length of .http://copranet.projects.eucc-d.de/files/000165_EUROSION_Humber_Estuary.pdf Also, the

Thames The River Thames ( ), known alternatively in parts as the River Isis, is a river that flows through southern England including London. At , it is the longest river entirely in England and the second-longest in the United Kingdom, after the R ...

tributary, the

River Churn The River Churn is a tributary of the River Thames in central England. It rises at Seven Springs in Gloucestershire and flows south for approximately to meet the Thames at Cricklade in Wiltshire. Its length from its source to the confluence wi ...

, sourced at Seven Springs, adds to the length of the Thames (from its traditional source at

Thames Head Thames Head is a group of seasonal springs that arise near the village of Coates in the Cotswolds, about three miles south-west of the town of Cirencester, in the county of Gloucestershire, England. The spring water comes from the limestone ...

). The

Churn Churn may refer to: * Churn drill, large-diameter drilling machine large holes appropriate for holes in the ground Dairy-product terms * Butter churn, device for churning butter * Churning (butter), the process of creating butter out of mil ...

/Thames' length at is therefore greater than the

Severn , name_etymology = , image = SevernFromCastleCB.JPG , image_size = 288 , image_caption = The river seen from Shrewsbury Castle , map = RiverSevernMap.jpg , map_size = 288 , map_c ...

's length of . Thus, the combined Churn/Thames river would top the list. Sue Owen et al., in their book on rivers, generally restrict the length to the parts that bear the same name. Thus the River Nene is quoted at , but would be around more if the variously named sources were included. Many of the above lengths are considerably different from Sue Owen's list, some longer and some shorter. Where a river ends in an estuary the conventional British approach has been to treat the river as ending at the end of the administrative zone. Thus the Severn ends at the mouth of the

Bristol Avon The River Avon is a river in the south west of England. To distinguish it from a number of other rivers of the same name, it is often called the Bristol Avon. The name 'Avon' is a cognate of the Welsh word , meaning 'river'. The Avon ...

and the Thames at the Yantlet Line. The currently accepted end of the Severn Estuary is about further, and the

Port of London The Port of London is that part of the River Thames in England lying between Teddington Lock and the defined boundary (since 1968, a line drawn from Foulness Point in Essex via Gunfleet Old Lighthouse to Warden Point in Kent) with the North Sea ...

's authority stretches now to Margate, further. Other countries have different conventions, making comparisons of limited value. Those rivers which empty into other (non-tidal sections of) rivers are indicated in the table thus*. In Yorkshire, the Aire, Derwent and Don all empty into a tidal section of the Yorkshire Ouse. The figures for

mean flow In fluid dynamics, the fluid flow is often decomposed into a mean flow and deviations from the mean. The averaging can be done either in space or in time, or by ensemble averaging. Example Calculation of the mean flow may often be as simple as the ...

are derived from those offered up by the National River Flow Archive, in particular the flow measured at the lowermost gauging stations on each named watercourse. Sometimes the figures of further downstream tributaries are combined with those of the

main stem In hydrology, a mainstem (or trunk) is "the primary downstream segment of a river, as contrasted to its tributaries". Water enters the mainstem from the river's drainage basin, the land area through which the mainstem and its tributaries flow.. A ...

river to provide a more realistic flow figure for the lowermost non-tidal stretch of a watercourse. Some major UK rivers (in terms of flow) are omitted from the list above simply because they are also short.

References

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United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

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Longest rivers of the United Kingdom

See also

References