Erith Marshes is an area of grazing marsh

Marsh

In geography, a marsh, or morass, is a type of wetland that is subject to frequent or continuous flood. Typically the water is shallow and features grasses, rushes, reeds, typhas, sedges, other herbaceous plants, and moss....

 beside the south bank of River Thames

River Thames

The River Thames flows through southern England. It is the longest river entirely in England and the second longest in the United Kingdom. While it is best known because its lower reaches flow through central London, the river flows alongside several other towns and cities, including Oxford,...

 in London

London

London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...

, England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

.
It is located next to the Crossness Sewage Treatment Works

Crossness

Crossness is a place in south-east London. It is situated in the London Borough of Bexley, close to the southern bank of the River Thames, to the east of Thamesmead, west of Belvedere and north-west of Erith. The place takes its name from Cross Ness, a specific promontory on the southern bank of...

 and is owned by Thames Water

Thames Water

Thames Water Utilities Ltd, known as Thames Water, is the private utility company responsible for the public water supply and waste water treatment in large parts of Greater London, the Thames Valley, Surrey, Gloucestershire, Wiltshire, Kent, and some other areas of in the United Kingdom...

. It is a site of metropolitan importance and situated at grid reference TQ483801, in the London Borough of Bexley

London Borough of Bexley

The London Borough of Bexley lies in south east Greater London, and is a borough referred to as part of Outer London. It has common borders with the London Borough of Bromley to the south, the London Borough of Greenwich to the west, across the River Thames to the north it borders the London...

. It can be accessed by London Buses

London Buses

London Buses is the subsidiary of Transport for London that manages bus services within Greater London, UK. Buses are required to carry similar red colour schemes and conform to the same fare scheme...

routes 177, 180, 229, 401 and 472.

The bulk of the marshes which once existed from Woolwich to Erith have now been built upon. The small part that remains is owned by Thames Water, who manage an award winning wildlife area and Tilfen Land. Note: At the time of writing Tilfen Land have planning permission to build an industrial park on around 33% of the remaining marshes and at its northern end Londons hugh waste incinerator has planning permission to be built. The expansion of Thamesmead to the west, Erith to the east and Belvedere north of the railway line and the earlier construction of Crossness Sewage Works makes this an area that will soon almost totally disappear within the next few years.