Epping Forest is an area of ancient woodland in south-east England, straddling the border between north-east Greater London and Essex. Formed in approximately 8000 BC after the last ice age, it covers nearly 6,000 acres (24 km²) and contains areas of grassland, heath, rivers, bogs and ponds. Stretching between Forest Gate in the south and Epping in the north, Epping Forest is approximately 18 km long in the north-south direction, but no more than 4 km from east to west at its widest point, and in most places considerably narrower. The forest lies on a ridge between the valleys of the rivers Lea and Roding; its elevation and consequent thin soil historically made it unsuitable for agriculture. Embankments of two Iron Age camps — Loughton Camp and Ambresbury Banks — can be found hidden in the woodland. It gives its name to the Epping Forest local government district.

old solitary oak, Epping forest

The name "Epping Forest" was first recorded in the 17th century; prior to this it was known as Waltham Forest (which gives its name to the present-day London borough). The forest is thought to have been given legal status as a royal forest by Henry I in the 12th century. This status allowed commoners to use the forest to gather wood and foodstuffs, and to graze livestock, but only the king was allowed to hunt there.

In Tudor times Henry VIII and Queen Elizabeth I hunted in the forest. In 1543 Henry commissioned a building, known as Great Standing, from which to view the chase at Chingford. The building was renovated in 1589 for Queen Elizabeth I and can still be seen today in Chingford. The building is now known as Queen Elizabeth's Hunting Lodge, and is open to the public as a museum.

Following disputes between landowners (who enclosed land) and commoners (who had grazing and cutting rights) the Epping Forest Act was passed in 1878. The Forest was saved by the Corporation of London from illegal enclosure. Epping Forest ceased to be a Royal Forest and the Crown's right to deer and venison was terminated. Pollarding was no longer allowed although grazing rights continued. This Act laid down a stipulation that the Conservators (i.e. the Corporation of London) shall at all times keep Epping Forest unenclosed and unbuilt on as an open space for the recreation and enjoyment of the people. When Queen Victoria visited Chingford on 6 May 1882 she declared "It gives me the greatest satisfaction to dedicate this beautiful Forest to the use and enjoyment of my people for all time" and it thus became "The People's Forest". The Corporation of London still own and manage Epping Forest in strict conformity with the Epping Forest Act without any money for its upkeep coming from local rates or taxes.

Although the Epping Forest Act almost certainly saved the forest from total destruction, it has to some extent had a deleterious effect on the area's biodiversity. Many of the trees in the forest were pollarded, which allowed light through to the woodland floor, increasing the numbers of low-growing plants. Since the Act, the pollarded trees have grown vast crowns of thick, trunk-like branches, which cut out most of the light to the underbrush. In addition, the area surrounding the forest is now to a great extent urbanised; the corresponding reduction in grazing has led to former areas of grassland and heathland being overcome by secondary woodland — this has been exacerbated by the majority of the forest's deer being enclosed to stop them being injured by vehicles on the major roads that run through the forest. In recent years, the Conservators have experimented with pollarding in selected areas of the forest, and a herd of English Longhorn cattle has been reintroduced to graze the forest floor.

The forest is the largest public open space in the vicinity of London and Essex - in fact it is the largest open space near any capital city in the world that has never been ploughed or cultivated.

Epping Forest is also the name of a town in Tasmania, Australia.

Epping Forest is also the name of a heavy metal rock band from Portugal.

"The Battle of Epping Forest" is the name of a song by the rock band Genesis on their 1973 album Selling England by the Pound.