Fulling mills were an essential part of the woollen trade: after cloth was woven, it was pounded or pressed with water and sometimes Fuller's earth to clean it, thicken the fibres, and give it a finished weight and texture. The process required a reliable water source and a mechanical hammer or stocks driven by a wheel, meaning these mills were typically built close to streams or rivers, and their presence in a townland is often the only surviving trace of a once-active local textile economy.