The townland of Lack in County Galway is home to one such recorded mill site, classified as a monument and therefore recognised as a place where the physical or documentary evidence of milling activity survives in some form, whether as structural remains, earthworks, or traces in the landscape.

Milling in rural Connacht was, for centuries, a cornerstone of local agricultural life. Horizontal mills, sometimes called Norse mills, were common in early medieval Ireland, their simple paddle-wheel mechanisms set directly in a fast-moving stream without the need for complex gearing. Later, vertical watermill technology became more widespread, often associated with landlord estates or improving tenants in the eighteenth and nineteenth centuries. Without more detailed records currently available for this particular site, it is not possible to say which tradition the Lack mill belongs to, nor when it was built or fell out of use. What the monument classification does confirm is that the site has been identified as worthy of formal protection, placing it in the same broad category as ringforts, church sites, and other features of the historic landscape.