Ravenglass Roman Bath House (also known as Walls Castle) is a ruined ancient Roman bath house at Ravenglass, Cumbria, England. Belonging to a 2nd-century Roman fort and naval base (known to the Romans as Glannoventa), the bath house is described by Matthew Hyde in his update to the Pevsner Guide to Cumbria as "an astonishing survival". The still standing walls are 13 ft (4 m) high, there are patches of the internal rendering, in dull red and white cement, and traces of the splayed window openings remain.