Lune Forest is a Site of Special Scientific Interest covering an extensive area of moorland in the Teesdale district of west Durham, England. In the north, where it adjoins the Upper Teesdale and Appleby Fells SSSIs, it extends from Mickle Fell eastward almost as far as Harter Fell, above the hamlet of Thringarth. Its southern limit is marked by the River Balder, upstream from Balderhead Reservoir, where it shares a boundary with Cotherstone Moor SSSI to the south. Grains o' th' Beck Meadows and Close House Mine SSSIs are entirely surrounded by Lune Forest, but do not form part of it.