Castle Douglas is built next to Carlingwark Loch in which traces of prehistoric crannogs can be found, evidence of early inhabitation of the area. A large bronze cauldron containing about 100 metal objects was found in Carlingwark Loch near Fir Island about 1866. The hoard of tools of iron and bronze is probably Romano-Belgic of the late first or early second centuries AD and is likely to have been a votive offering. It is now in the National Museums of Scotland in Edinburgh. To the North of the town Glenlochar is the site of two successive Roman forts, the first being erected during the invasion of Agricola and the second during the Antonine period. They appear to have been for cavalry units and evidence has been found that a "vicus" grew up around them. They were abandoned completely about 160.