The Old River Lea is the natural channel of the River Lea that splits from the Hackney Cut (or River Lea Navigation) at Lea Bridge.
The Old River follows a meandering course, starting at Lea Bridge Weir and rejoins the River Lee Navigation below Old Ford Lock.
The removal of the meanders led to changes in the political boundaries between boroughs/districts and between the counties of Essex and London/Middlesex. Disputes grew up around the proposed boundary changes.
The level of the ground on either side has been raised up. In the case of Hackney Marsh, this was due to the dumping the rubble from bombed buildings. This results in a distinct edge profile. The western river bank has a lower terrace, lined with mature native trees (subject to occasional flooding), and an upper terrace, the level of the Marshes and the perimeter footpath.
The Old River forms the eastern boundary of Hackney Marshes and is the boundary between the London Boroughs of Hackney and Waltham Forest.
A number of meanders in the river were removed in the late 19th and early 20th century in the hope that this would reduce the severity of floods. This included ‘The Friends’ and two more meanders below this, opposite Hackney Marsh.
The entire length of the Old River was affected by the tidal reach until the recent construction of Prescott Lock, which impounded the River.
The Old River Lea is traversed by the Friends Bridge and the bridge to the East Marsh.