Hackney Marshes is an area of grassland comprising 337 acres on the western bank of the River Lea in the London Borough of Hackney.

Originally, it was a true marsh, formed by the periodic flooding of the River Lea. However, after multiple human interferences including continuous drainages since the Medieval Times, this area can no longer be considered a wilderness environment. Rubble from World War II bombed buildings as spread on the Marshes turned them from marshland to amenity grassland. As a periodic floodplain, it could not be occupied permanently, so the main use was as pasture land.

In 1890, the Marshes became an area preserved by London County Council and a public area since 1893. Currently, this area is managed by the Hackney Council and is used for football, cycling, yoga, rugby, camping, conservation and recreation, including 72 full sized football pitches.