Leyton Marsh is located in Leyton in the London Borough of Waltham Forest.
The marsh is bordered by the Walthamstow Marshes to the north, and by Coppermill Fields, the Lee Navigation and the River Lee Flood Relief Channel. Much of the original area has been taken over for other uses. The remaining open land is split into two distinct areas:
Other areas which were historically part of Leyton Marshes are now put to other uses:
Lammas Lane, despite historic associations, is buried in an industrial estate alongside the railway.
Leyton Marsh was originally more extensive open marsh, historically drained by means of open drainage ditches. The marsh is former Lammas Land: the land was divided into strips, which were cultivated to grow hay for winter feed. Parishioners had ancient rights to graze cattle and horses between 1 August (after the hay harvest) and 25 March.
In the 19th century the marsh was polluted by sewage from the extensive new residential developments in Walthamstow and Leyton.
By the 19th century the character of the marsh changed. Many acres were bought and built on by railway, water and gas companies. In the early 1890s the East London Waterworks Company erected fences, which angered local people. On Lammas Day in 1892, a large demonstration took place on the marsh and the fences were taken down. The locals set up the Leyton Lammas Lands Defence Committee and successfully challenged the water company in court. This led to the Leyton Urban District Council Act 1904, which provided that the marsh would be kept as an open space, in return for local people giving up Lammas rights. The fields at Marsh Lane did not come under this agreement and remain as Lammas land.
During World War II, a V-2 rocket landed and exploded on the marsh; the crater is still visible seven decades later. After the war, the marsh was used to dump rubble from The Blitz.