Lancaut is a deserted village and former civil parish, now in the parish of Tidenham, in the Forest of Dean district, in Gloucestershire, England, located alongside the River Wye, around two miles north of Chepstow. It occupies a narrow-necked promontory formed by a curve of the river, which acts as the border between England and Wales. Little remains of the village today, except for the roofless church of St. James.

Tidenham is a village and civil parish in the Forest of Dean of west Gloucestershire, England, adjoining the Welsh border. Tidenham is bounded by the River Wye to the west and the River Severn to the south. Offa's Dyke runs through the western part of the parish, terminating at Sedbury cliff above the River Severn.