So, You Think You Know The Thames? Top Facts About London’s Famous River


The River Thames has always been one of the most recognisable waterways in the world. From the opening of famous soap Eastenders to the iconic emblem of Tower Bridge, instantly recognisable in all corners of the globe, the city has always worn its favourite river proud and loud. For guests at the London City Suites by Montcalm Chiswell Streetit might be the first thing you want to see when you visit London. With some of the best attractions dotted along its banks, the river is incredibly hard to miss and acts as the spine for the city. 


With thousands of years of history, the River Thames still holds many secrets, many of which can be discovered at great city museums such as the Museum of London, and can be explored through events, tours and even from a walk on the banks themselves. Below are some of our favourite facts about the river, giving you a little more insight into one of the city’s grandest landmarks.

The river spans 215 miles

Stretching from Gloucestershire through Oxford, Reading and London, the Thames really makes its mark. As the only drainage basin of London, the Thames flows through the UK capital and into the North Sea through smaller tributaries. Following the Thames not only takes you straight through the heart of the city but through many of the most beautiful natural landscapes in the South of England.

And is the second-longest in England

The only river in England that’s bigger than the Thames is the River Severn which spans for 220 miles and runs through Shropshire, Worcestershire and the Cambrian Mountains. At just 5 miles longer than the Thames, it only just beats the Thames on length, and whilst it runs through some historic towns like Shrewsbury and the medieval Tewkesbury, they don’t quite have the same tourist pull as London does. 

Its source is a field in Gloucester

Big things almost always have small beginnings. A field in Gloucester claims the title of being the source of the Thames. The Thames Head is easily visitable in Thames Head Gloucestershire. However, the true source is contested and some believe that it is actually at Seven Springs, which is known to be the source of one of the Rivers tributaries. Visit the leafy fields and decide for yourself!

The river boasts a whopping 200 bridges

Across its 215 miles, it’s not surprising to find that there are many bridges along its path. That’s almost one bridge per mile, making it one of the most abundant bridge bearers in the country. This is no surprise, no doubt guests at the Montcalm London Hotel Spa will want to cross the other side of London on their visit. 

The Thames has 80 islands

Across its 215 miles, the Thames also has about 80 islands nestled within it. Some of these have become well-known landmarks in and of themselves, including Eel Pie Island in Twickenham and Monkey Island in Bray.

It goes by The Isis in Oxford

Before it grows in size in Dorchester, the River Thames smaller leg, growing from the Cotswolds is known as the Isis. The reason for this change in name, especially in parts of Oxfordshire, is that the first known name for the Thames, dating back thousands of years, is Tamesis. This name was incorrectly assumed to be a combination of “Thame” and “Isis”, hence the splitting of the word to refer to two parts of the same river. Despite the mistake from ancient Thames dwellers, the name has stuck.

London Bridge is the oldest in London

It’s no surprise that London Bridge’s name seems to represent the whole city, it was named when the UK Capital was still in its infancy. The Bridge stands where many have before it and before it was even given its name in the 13th century, many more had stood where London Bridge has. Dating back to the Roman era and perhaps even before their AD55 built floating pontoon bridge, which was the reason why ancient London became such a thriving trading town.

And has been rebuilt several times

In the late 11th century, a tornado destroyed London Bridge, whilst earlier ones were destroyed by war and timber propelled fires. After several attempts to build it from timber, it was eventually made from Stone and then finally rebuilt once more in the 1920s when the gove3rnment realised that the bridge was actually sinking into the Thames.

Humans have used the river since pre-Roman times

Whilst the Romans created the basis for what we now know as London, the existence of a bridge in the same area predates their conquest. With ancient settlers in the area using it as the main way to cross the river, it’s surprising to think that for so many centuries, the Thames was the only bridge over the area of what would become London.

London uses the Thames for two-thirds of its drinking water

Looking into the present murkiness of the Thames, you might be horrified to learn that we actually use it for two-thirds of London’s drinking water! In terms of size, this is not surprising, and the fact that the river comes from a natural spring in the fields of Gloucestershire should at least give you peace of mind that its source is natural and fresh.

But don’t worry, it’s treated!

For your peace of mind though, it’s good to remember that the Thames water service is responsible for treating our water. With large reservoir reserves in Walthamstow and acres of land reserved for storing it, the water supplies for London are abundant and well maintained. You can visit the Walthamstow reservoir in the idyllic Walthamstow Marshes area of East London.

Seahorses have been found in the Thames

Whilst eels have become famous for making their home in the Thames, the most unique river dweller in the Thames is possibly the tiny seahorses that are sometimes found in its clearer parts.

And seals like it too!

Whilst rarely spotted in London, seals have been known to swim up and down the Thames, especially in the Richmond, Hammersmith and Thames estuary area. These cute creatures can sometimes migrate from the shores of the North Sea where the Thames’s mouth is. Porpoises and Dolphins have sometimes been spotted in the Thames too, making for a really rare but cute sight.