Lee Valley Regional Park is a 10,000-acre (40 km2) 26 miles (42 km) long linear park, much of it green spaces, running through the northeast of Greater London, Essex and Hertfordshire from the River Thames to Ware, through areas such as Stratford, Clapton, Tottenham, Enfield, Walthamstow, Cheshunt, Broxbourne and Hoddesdon in an area generally known as the Lea Valley. Greater London's largest park, Lee Valley Park is more than four times the size of Richmond Park, extending beyond Greater London's borders into the neighbouring counties of Hertfordshire and Essex.
The park follows the course of the River Lea (Lee) along the Lea Valley from Ware in Hertfordshire through Essex and the north east of Greater London, through the Queen Elizabeth Olympic Park to East India Dock Basin on the River Thames. The park is managed by Lee Valley Regional Park Authority and is made up of a diverse mix of countryside areas, urban green spaces, heritage sites, country parks, nature reserves and lakes and riverside trails, as well as leading sports centres covering an area of over 10,000 acres (40 km2). It is crossed by a number of roads and railways.
There are several major reservoirs and multiple water courses (rivers and canals) within Lee Valley Park, both to carry the river flow, and also to provide navigable waterways and flood relief channels.