Summary In 1975—76 the extra-mural bathhouse of Bothwellhaugh Roman fort near Motherwell, Lanarkshire, was completely excavated prior to flooding of the site. The bathhouse, which probably overlay a small native settlement, was in use during the Antonine phase of the Roman occupation of Scotland (AD 142—c. 165). The bathhouse consisted of a vestibule, a cold room (Frigidarium) and cold plunge bath, two warm rooms (the First and the Second Tepidarium), a hot room (Caldarium) with adjacent hot bath, and a furnace room (Praefurnium). Three main phases of use were detected. After the building ceased to function as a bathhouse, it was occupied by squatters who adapted parts of the structure to their own needs and left evidence of their presence in a large quantity of animal bone. Radiocarbon dates on this bone indicate activity in the 2nd or 3rd centuries ad.