Thetford Forest is the largest lowland pine forest in Britain and is located in a region straddling the north of Suffolk and the south of Norfolk in England. It covers over 19,000 ha in the form of a Site of Special Scientific Interest.

Thetford Forest was created after the First World War to provide a strategic reserve of timber, since the country had lost so many oaks and other slow-growing trees as a consequence of the war’s demands. It is managed by the Forestry Commission. The creation of the forest destroyed much of the typical Breckland environment of gorse and sandy ridges, ending the frequent sand blows (where the wind picked up sand and blew it across the land reducing visibility). However, this environment was itself man-made, since the area had been denuded by flint-mining, the construction of rabbit warrens and other activities. Grimes Graves is located within the forest.