The Forest of Dean (Forest of Dean English: Vorest o’ Dean) is a geographical, historical and cultural region in the western part of the county of Gloucestershire, England. It forms a roughly triangular plateau bounded by the River Wye to the west and northwest, Herefordshire to the north, the River Severn to the south, and the City of Gloucester to the east.
The area is characterised by more than 110 square kilometres (42 sq mi) of mixed woodland, one of the surviving ancient woodlands in England. A large area was reserved for royal hunting before 1066, and remained as the second largest crown forest in England, after the New Forest, 105 kilometres (65 mi) to the southeast. Although the name is used loosely to refer to the part of Gloucestershire between the Severn and Wye, the Forest of Dean proper has covered a much smaller area since the Middle Ages. In 1327, it was defined to cover only the royal demesne and parts of parishes within the hundred of St Briavels, and after 1668 comprised the royal demesne only. The Forest proper is within the civil parishes of West Dean, Lydbrook, Cinderford, Ruspidge, and Drybrook, together with a strip of land in the parish of English Bicknor.