Thames The River Thames

The tidal section[edit]
Main article: Tideway

London Stone at Staines, built in 1285 marked the customs limit of the Thames and the City of London's jurisdiction

Waterstand of Thames at low tide (left) and high tide (right) in comparison at Blackfriars Bridge in London
Below Teddington Lock (about 55 miles or 89 kilometres upstream of the Thames Estuary), the river is subject to tidal activity from the North Sea. Before the lock was installed, the river was tidal as far as Staines, about 16 miles (26 km) upstream.^[24] London, capital of Roman Britain, was established on two hills, now known as Cornhill and Ludgate Hill. These provided a firm base for a trading centre at the lowest possible point on the Thames.^[25]
A river crossing was built at the site of London Bridge. London Bridge is now used as the basis for published tide tables giving the times of high tide. High tide reaches Putney about 30 minutes later than London Bridge, and Teddington about an hour later. The tidal stretch of the river is known as "the Tideway". Tide tables are published by the Port of London Authority and are available online. Times of high and low tides are also posted on Twitter.
The principal tributaries of the River Thames on the Tideway include the rivers Crane, Brent, Wandle, Ravensbourne (the final part of which is called Deptford Creek), Lea (the final part of which is called Bow Creek), Roding, Darent and Ingrebourne. At London, the water is slightly brackish with sea salt, being a mix of sea and fresh water.
This part of the river is managed by the Port of London Authority. The flood threat here comes from high tides and strong winds from the North Sea, and the Thames Barrier was built in the 1980s to protect London from this risk.
The Nore is the sandbank that marks the mouth of the Thames Estuary, where the outflow from the Thames meets the North Sea. It is roughly halfway between Havengore Creek in Essex and Warden Point on the Isle of Sheppey in Kent. Until 1964 it marked the seaward limit of the Port of London Authority. As the sandbank was a major hazard for shipping coming in and out of London, in 1732 it received the world's first lightship. This became a major landmark, and was used as an assembly point for shipping. Today it is marked by Sea Reach № 1 Buoy.^[26]
Islands[edit]
Main article: Islands in the River Thames

London City Airport is on the site of a dock
The River Thames contains over 80 islands ranging from the large estuarial marshlands of the Isle of Sheppey and Canvey Island to small tree-covered islets like Rose Isle in Oxfordshire and Headpile Eyot in Berkshire. They are found all the way from the Isle of Sheppey in Kent to Fiddler's Island in Oxfordshire. Some of the largest inland islands, for example Formosa Island near Cookham and Andersey Island at Abingdon, were created naturally when the course of the river divided into separate streams.
In the Oxford area the river splits into several streams across the floodplain (Seacourt Stream, Castle Mill Stream, Bulstake Stream and others), creating several islands (Fiddler's Island, Osney and others). Desborough Island, Ham Island at Old Windsor and Penton Hook Island were artificially created by lock cuts and navigation channels. Chiswick Eyot is a landmark on the Boat Race course, while Glover's Island forms the centre of a view from Richmond Hill.
Islands of historical interest include Magna Carta Island at Runnymede, Fry's Island at Reading, and Pharaoh's Island near Shepperton. In more recent times Platts Eyot at Hampton was the place where Motor Torpedo Boats (MTB)s were built, Tagg's Island near Molesey was associated with the impresario Fred Karno and Eel Pie Island at Twickenham was the birthplace of the South East's R&B music scene.
Westminster Abbey and the Palace of Westminster (commonly known today as the Houses of Parliament) were built on Thorney Island, which used to be an eyot.