The Severn Bridges crossing near the mouth of the River Severn.
The Severn Bridges crossing near the mouth of the River Severn.
The River Thames in London.
The River Thames in London.
The River Tay in Perth, by measured flow the largest in Great Britain.
The River Tay in Perth, by measured flow the largest in Great Britain.

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

Longest rivers of the United Kingdom

Rank River Length (miles) Length (km) Mean Flow (m3/s)[1] Country
1 River Severn[2] 220 354 107.4 Wales/England
2 River Thames[2] 215 346 65.4 England
3 River Trent[2] 185 297 89.0 England
4 River Wye[3] 155 250 73.1 Wales/England
5 River Great Ouse[2] 143 230 15.6 England
6 River Ure/River Ouse, Yorkshire 129 208 69.8 England
7 River Tay[2] 117 188 179.0 Scotland
8 River Clyde 109 176 48.5 Scotland
9 River Spey 107 172 65.7 Scotland
10 River Nene[2] 100 161 9.3 England
11 River Bann / Lough Neagh 99 159 92.2 Northern Ireland
12 River Tweed[2] 96 155 81.7 Scotland/England
13 River Avon, Warwickshire 96 154 17.3 England
14 River Eden, Cumbria 90 145 53.7 England
15 River Dee, Aberdeenshire 87 140 47.8 Scotland
16 River Witham 82 132 5.2 England
17 River Teme 81 130 18.2 Wales/England
18= River Don, Aberdeenshire[2] 80 129 21.3 Scotland
18= River Foyle 80 129 58.8 Northern Ireland/Republic of Ireland
20 River Usk[4] 78 125 28.6 Wales
21 River Teifi[5] 76 122 29.5 Wales
22= River Tywi 75 121 39.9 Wales
22= River Ribble 75 120 34.0 England
22= River Avon, Bristol 75 120 22.2 England
25 River Tyne[2] 73 118 45.2 England
26 River Derwent, Yorkshire 72 115 17.4 England
27= River Aire 71 114 36.5 England
27= River Nith 71 114 36.5 Scotland
29= River Tees 70 113 22.2 England
29= River Medway 70 113 11.7 England
29= River Mersey 70 113 37.1 England
32= River Dee, Wales[2] 70 112 34.1 Wales/England
32= River Don, South Yorkshire 70 112 16.3 England

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/ River Ouse/Humber system would come fourth in the list, with a combined length of 161 miles (259 km); and the River Trent/Humber system would top the list with their combined length of 222 miles (357 km).[6] Also, the Thames tributary, the River Churn, sourced at Seven Springs, adds 14 miles (23 km) to the length of the Thames (from its traditional source at Thames Head). The Churn/Thames' length at 229 miles (369 km) is therefore greater than the Severn's length of 220 miles (354 km). 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 100 miles (160 km), but would be around 5 miles (8 km) 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.[2]

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 and the Thames at the Yantlet Line. The currently accepted end of the Severn Estuary is about 18.5 miles (29.8 km) further, and the Port of London's authority stretches now to Margate, 30 miles (48 km) further. Other countries have different conventions, making comparisons of limited value.

See also

References

  1. ^ https://nrfa.ceh.ac.uk/data/search
  2. ^ a b c d e f g h i j k Owen, Susan; et al. (2005). Rivers and the British Landscape. Carnegie. ISBN 978-1-85936-120-7.
  3. ^ "SSSI Citation River Wye (upper Wye)" (PDF). Natural Resources Wales. Retrieved 14 November 2020.
  4. ^ "Usk management catchment Summary" (PDF). Natural Resources Wales. Retrieved 14 November 2020.
  5. ^ - River Teifi - CCW Archived 2014-02-21 at the Wayback Machine
  6. ^ http://copranet.projects.eucc-d.de/files/000165_EUROSION_Humber_Estuary.pdf