A set of four gravel beach ridges at Caerlaverock on the north shore of the Solway Firth are shown to have formed in the twelfth and thirteenth centuries ad, the most recent such deposits on this coast. They were investigated by geomorphological mapping, altitudinal survey, sediment stratigraphic and clast lithological analyses to establish their internal structure and sediment sources. Gravel clasts were in part transported from rock outcrops on the west side of the Nith Estuary, and this observation implies that the current estuarine sediment fills of the inner firth were then far less extensive. The data suggest that the Medieval period was one of major coastal change. Fluctuations in sediment supply are demonstrated from the clast lithological analyses which may relate to shifts in the directions of storm tracks.