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. 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 Docks 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.

The River Lea is in the East of England and Greater London. It originates in Bedfordshire, in the Chiltern Hills, and flows southeast through Hertfordshire, along the Essex border and into Greater London, to meet the River Thames at Bow Creek. It is one of the largest rivers in London and the easternmost major tributary of the Thames.