Magna Carta Island

Magna Carta Island is on the right bank (North East) and, as far as navigation is concerned, is only by courtesy now an Island. The only channel is to the South West of it.
The name comes from this being the traditional site of the signing of Magna Carta. All the other Magna Carta references are to Runnymede, on the Left bank, the other side of the river.
1215: June 15th, the signing of Magna Carta

1810: John Evans -

Near Runnymede, on the river Thames, is Magna Charta Island, said to be the temporary and fortified residence of the Barons, to which they retired from the pressure of the surrounding multitude assembled on Runnymede, that they might have a better opportunity of obtaining the signature of King John confirming the rights held under that palladium of our Liberty; it is now nearly covered with willows that shade the hut of the fisherman.

1859:  Mr & Mrs Hall –

Cottage on Magna Charta Island, 1859
Cottage on Magna Charta Island, 1859

In the island which forms so charming a feature in the landscape, the Harcourts have built a small Gothic cottage – an altar house, so to call it.

Actually now its called Chapel - and is said to have been sold for $20 million dollars (2014).

The Seven bedroom 'Chapel' on the site where Magna Carta is said to have been signed

It contains a large rough stone, which tradition, or fancy, describes as that on which the parchment rested when the King and the barons affixed their signatures to “the Charter”.  It has the following inscription:

15 June 1215

1870:  Magna Carta Cottage, Henry Taunt

Magna Carta Cottage, Henry Taunt, 1870
Magna Carta Cottage, Henry Taunt, 1870
© Oxfordshire County Council Photographic Archive; HT01282

Lantern Slide (1883-1908) - "Picnic at Ankerwyke" [Magna Carta Cottage]
Pictures by W.C.Hughes. Thanks to Pat Furley, research by Dr Wilson.

1885: Dickens's Dictionary of the Thames -

Magna Carta Island ... one of the most charming islands on the river, and of historical interest as the scene of that little arrangement between King John and his barons, which, as "every schoolboy knows", was the foundation of the freedom of England. ...
The usual uncertainty and vagueness which characterise all history step in even at what ought to be so very simple a matter as this. Tradition undoubtedly assigns the honour of being the scene of signature to the island. But in the charter itself it is said to be given at Runningmede, so that it would seem to be doubtful whether the finishing stroke was given to the palladium of English liberties on this island itself. ...

1889: Jerome K Jerome -

We had originally intended to go on to Magna Charta Island, a sweetly pretty part of the river, where it winds through a soft, green valley, and to camp in one of the many picturesque inlets to be found round that tiny shore.  But, somehow, we did not feel that we yearned for the picturesque nearly so much now as we had earlier in the day.  A bit of water between a coal-barge and a gas-works would have quite satisfied us for that night.  We did not want scenery.  We wanted to have our supper and go to bed.  However, we did pull up to the point - "Picnic Point," it is called - and dropped into a very pleasant nook under a great elm-tree, to the spreading roots of which we fastened the boat.
We went over to Magna Charta Island, and had a look at the stone which stands in the cottage there and on which the great Charter is said to have been signed; though, as to whether it really was signed there, or, as some say, on the other bank at "Runningmede," I decline to commit myself.  As far as my own personal opinion goes, however, I am inclined to give weight to the popular island theory.  Certainly, had I been one of the Barons, at the time, I should have strongly urged upon my comrades the advisability of our getting such a slippery customer as King John on to the island, where there was less chance of surprises and tricks.

Magna Carta in 20 places by Derek J Taylor says:

Runnymede isn't a specific spot. It covers an area of several square miles along the River Thames halfway between Windsor and Staines, plenty of room in fact for the site of the birth of Magna Carta to be the subject of as many errors and falsifications as anything else associated with the Great Charter.
There's a persistent myth, given worldwide credence by Jerome K.Jerome in his 1889 best-selling novel Three Men in a Boat, that the great event happened on an island in the Thames, across from the meadow at Runnymede. Jerome treats us first to rousing images of slippery' King John and his 'French' mercenaries facing the grim ranks of the barons' men' before they all step ashore "on the bank of the little island that from this day will bear the name of Magna Carta and a great shout cleaves the air and the great cornerstone in England's temple of liberty has, now we know, been firmly laid.
There's even a stone in the grounds of a cottage on the island that marks the spot where the Great Charter was 'signed'. Three Men in a Boat is one of the funniest books ever written. But, historically speaking, it's rubbish - charming rubbish but rubbish nonetheless. Even so it is still popularly believed today. Just to be clear, nothing, not the thinnest sliver of evidence, supports the idea that John and the barons assembled on any island.
And prepare to be shocked. There are doubts too about the positioning of the official memorial itself. According to the Ordnance Survey map for south-west London, it's in a field towards the bottom of a gentle slope. And that's the problem It's shown on the side of a hill, not a steep hill, but a hill nevertheless, running parallel with the river. It's called Cooper's Hill. However, that doesn't fit with contemporary accounts. Magna Carta itself ends with the words, "Given in the meadow that is called Runnymede between Windsor and Staines, 15 June'. The name Runnymede is Anglo-Saxon, and doesn't mean, as we might imagine, 'runny', i.e. a 'wet' meadow but derives from the word 'runieg' meaning meeting place. Since as far back as at least the ninth century, the meadow at Runnymede had been somewhere where kings gathered to consult their vassals, and where enemies could meet to negotiate in safety. Security was guaranteed because it was bounded by the River Thames to the north, by a stream to the west, and by marshy ground to the east and the south It was almost an island, not a real island, but more like a reverse oasis of dryness surrounded by water. It was accessible only by the causeway road from Windsor in one direction and from Staines in the other. This was important because King John and the barons had a deep distrust for each other. And the last place either would have chosen for their meeting was one where attack was possible from nearby high ground.
Finding the exact spot today that fits that definition is no easy task. Over a period of 800 years, marshland has been drained so houses and roads could be built and small streams can disappear at the same time. But what doesn't tend to rise up out of the earth unexpectedly over just a few centuries is a 3-mile-long hill. In 1215 it would have been exactly where it is now. So the conclusion seems clear:
Magna Carta cannot have been born where the official memorial is shown on the map, on the side of Cooper's Hill, nor can the big event even have taken place in front of the memorial where the stretch of meadow is exposed to attack from that hill.
So, where did it take place? What we're looking for is a section of flat land alongside the Thames, which is not overlooked by sloping ground to the south. And the OS map shows that the only place that meets that specification is right where they've built the Runnymede- on-Thames Hotel and Spa. In fact, given that the two opposing camps would have occupied several hundred square yards of meadow, the betting must be that much of the site where the Great Charter was born lies somewhere under the hundred thousand tons of concrete and tarmac that make up the several roundabouts, bridges, underpasses and slip roads by the M25 motorway -
Truth can be ugly.

Click link on Google map at top of page

1906: Magna Charta Island, Mortimer Menpes -

Magna Charta Island, Mortimer Menpes, 1906
Magna Charta Island, Mortimer Menpes, 1906