The inhabitants of most urban and rural communities in both Britain and Ireland during the later medieval period would have lived a relatively short distance from either a watermill or windmill. This chapter examines the most recent archaeological evidence for water- and wind-powered mills in later medieval Britain. The use of water power, in particular, was widespread in the later medieval period for a wide range of industrial activities. However, during this same period nearly all of the grain harvest was processed in either wind- or water-powered mills. The archaeological record also demonstrates a large degree of continuity, from the late Roman and early medieval periods, in the design of waterwheels and the mechanisms they actuated.