Rivers are a natural part of the UK’s beauty and provide many important functions. These rivers vary in size, from small streams to large bodies of water, but they all have an important role to play in British life and scenery. The longest river in the United Kingdom is the Severn River which flows through England and Wales. It runs from its source near Gloucester to its mouth on the Bristol Channel between Cardiff and Weston-Super-Mare

Is the Thames the longest river in the UK?

No, the Thames is not the longest river in the UK. It’s the second-longest river in the British Isles.

Which is the longest river in the United Kingdom?

The longest river in the UK is the Severn.

The Severn River is the longest river in the UK, measuring 220 miles in length. It starts on Mount Plynlimon in Powys, Wales and flows east then northeast to Shrewsbury before turning south through Bewdley and Gloucester towards the Bristol Channel. The river’s mouth is located near the city of Cardiff in South Wales. Plynlimon is the source of three rivers which all spring within a few hundred yards of each other. The three are known as Wales’ shortest, most beautiful, and longest rivers, namely the Rheidol, the Wye and the Severn.

The Severn flows through a number of towns and cities, including Gloucester, Worcester, Cheltenham, Shrewsbury and Bristol. It is navigable for much of its length and was once an important route for transportation. Now, most of the craft on the Severn above Gloucester are recreational. It also provides hydroelectric power to the British national grid. The river is popular for fishing, and it supports a variety of wildlife habitats as well as much of the water for England’s canal system.

Do you know what is the longest river in Europe, and what is the longest river in the world?

10 longest rivers in the UK

River Severn

• The River Severn is the longest river in Great Britain. 
• the river carries the biggest volume of water in all of England and Wales.
• It rises in mid-Wales in the Cambrian Mountains, at 610 m 
• The river flows through Shropshire, Worcestershire and Gloucestershire before emptying into the Bristol Channel.

River Thames

• The River Thames, known alternatively in parts as the River Isis, is a river that flows through southern England including London. With a length 346 km, the Thames is the longest river in England and the second-longest in the UK. It flows through Oxford (where it is called the Isis), Reading, Henley-on-Thames and Windsor
• The Thames valley drains the whole of Greater London and a large proportion of of central England

River Trent

• The River Trent is the third-longest river in the United Kingdom. 
• Trent flows through and drains most of the metropolitan central and northern Midlands south and east of its source north of Stoke-on-Trent
• The river is known for flooding after heavy storms and which in past times often caused the river to change course

River Great Ouse

• The River Great Ouse is a river in England, flowing through Buckinghamshire, Bedfordshire, Cambridgeshire and Norfolk. 
• With a length of 230 km, it is the fifth longest river in the United Kingdom. 

River Wye

• The Wye springs in Wales on Plynlimon, near the source of the severn and borders England, before joining the Severn estuary. It runs though tne beautiful borderlands of south Wales and is important for nature conservation and recreation. Recently however it has become severely polluted by runoff from factory egg and chicken farming and has been the subject of environmental demonstrations.

20 longest major rivers in the UK – Table

	River	Length in miles	Length in km	Country
1	Severn	220	354	Wales and England
2	Thames	215	346	England
3	Trent	185	297	England
4	Great Ouse	143	230	England
5	Wye	135	215	Wales and England
6	Ure / Ouse	129	208	England
7	Tay	117	188	Scotland
8	Spey	107	172	Scotland
9	Clyde	106	172	Scotland
10	Tweed	96	155	Border of Scotland
11	Avon	96	154	England
12	Nene	91	148	England
13	Eden	90	145	England
14	Dee	87	140	Scotland
15	Witham	82	132	England
16	Teme	81	130	England
17	Don	80	129	Scotland
18	Bann	76	122	Northern Ireland
19	Ribble	75	120	England
19	Avon	75	120	England

Longest UK Rivers

Privacy Policy Disclaimer

This website uses affiliate links for income and support.

If you like our website, please consider using these links. You will be directed to the vendor, and we will get a small commission on your purchase price at no increased cost to you.

We have researched facts stated here as far as practicable but please check anything critical before committing your time and money. We do not claim any special knowledge or expertise, and we are not consultants for our readers.