The Longest Rivers in the United Kingdom

When it comes to the UK landscape, much more than one river runs through it. But which runs the furthest? We’re exploring the longest rivers in the United Kingdom.

Travel and Exploration
24 November 2022

Rivers are an essential part of the United Kingdom’s ecosystem. They provide critical habitat for plants and animals, they play a role in the water cycle, and they provide people with many benefits, including drinking water, transportation, recreation, and more.

In this article, we’ll explore the longest rivers in the United Kingdom, learning about characteristics like their routes and wildlife. As you would expect of such a small island, even the longest rivers UK topography has to offer cannot compete with the world’s longest rivers. Nevertheless, they are brimming with wildlife, activity and history. Let’s begin with the longest river in Great Britain and the UK.

1. River Severn

The river Severn at Ironbridge, Shropshire, England (Photo: Photos by R A Kearton via Getty Images)

At 220 miles long, the River Severn is the longest river in Great Britain and in the UK. It rises in the Welsh Cambrian mountains and crosses into England, travelling through the counties of Shropshire, Worcestershire and Gloucestershire. It eventually empties into the Bristol Channel.

The river is home to a number of species of fish, including salmon, grayling, and trout. In a historical context, three miles of the Severn within Shropshire are part of the UNESCO site of Ironbridge Gorge, which is renowned for its role in the industrial revolution. This is also the location of the world’s first iron bridge, simply called The Iron Bridge. This is one of the three bridges crossing the Severn that have grade I listing for being bridges of exceptional interest. The other two are Bewdley Bridge and Severn Bridge,

The river is tidal for about half of its length and, in addition to its longest river of Britain title, it is also the most voluminous, with an average flow rate of 3,800 cubic feet per second.

2. Thames

A panoramic view across the Thames at sunrise (Photo: George W Johnson via Getty Images)

Liquid history. Those two words, used by the politician John Burns in 1929 to describe the River Thames, encapsulate so much. And it’s a history spanning some 30 million years. One in which this river remembers a time before Britain became an island. Not least because back then it was not the second longest UK river, but a tributary of the River Rhine.

Today, the iconic River Thames runs east for around 215 miles from its source in Thames Head in Gloucestershire. Or so convention dictates. Some consider its source to be in Ullenwood, Gloucestershire, which would make it five miles longer and challenge the River Severn for the title of longest river of Britain. Whatever the case, it is definitely the longest river in Great Britain solely within England.

Along its journey, the Thames flows through Oxford, Reading, Windsor and, of course, the capital, London. Its banks host some of the most famous buildings on the planet, from the Palace of Westminster and the Tower of London to Hampton Court Palace and the Tate Modern.

3. Trent

A footpath runs alongside the River Trent (Photo: Steve_Bramall via Getty Images)

From its source in Staffordshire’s Biddulph Moor, the River Trent travels through the counties of Derbyshire, Leicestershire, Nottinghamshire, Staffordshire and Yorkshire before ending at its mouth at the Humber Estuary. From there, its waters empty into the North Sea. Birmingham, Nottingham and Leicester are just three of the major cities of England’s Midlands that it drains along the way.

So, how long is the third longest river in the United Kingdom? Most sources say 185 miles, although the figure ranges as low as 170 miles.

Amongst its claims to fame, the river is known for being the historic demarcation between northern and southern England, at one time known as the uplands and lowlands. It has 42 tributaries and it’s often said that Trent’s name derives from the Celtic for ‘strong flood’.

4. Wye

River Wye from the Yat Rock viewpoint (Photo: James Osmond via Getty Images)

Flowing through Wales and England, the River Wye, Afon Gwy in Welsh, is one of the longest UK rivers. It is, in fact, considered the fourth longest river in the UK, with a length of around 155 miles. Along its journey, the river is fed by several tributaries, including the River Lugg, Afon Elan, and River Trothy.

Human activity has had significant implications for the river, causing extensive pollution and depletion of wildlife habitats. Whilst this is still very much an issue, conservation efforts have improved matters. Today, over thirty species of fish are known to inhabit the River Wye, including bullhead, lamprey and salmon. Otters have returned to the Wye and live there alongside mink and water voles.

5. Great Ouse

River Ouse, Cambridgeshire (Photo: Claire Reynolds via Getty Images)

The Great Ouse is a river in eastern England that flows for about 160 miles from its source in the county of Northamptonshire to its mouth in The Wash, a large bay on the east coast. The Great Ouse is one of the United Kingdom’s major rivers and is an important waterway for both commerce and recreation.

The UK’s Longest Rivers

Aerial View of London cityscape with River Thames at twilight (Photo: TangMan Photography via Getty Images)

And so we reach the end of this exploration of the longest UK rivers, offering just a glimpse into the many rivers UK topography has to offer. Each has its own story, from the longest river in Great Britain, right through to the smallest.


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