Corn mills of this kind were once a fixture of rural Irish life, small-scale water-powered structures built to grind grain for local communities, typically comprising a millrace, a waterwheel, and a series of grinding stones housed in a modest stone building. The fact that this one survives even as a ruin marks it as a physical remnant of an agricultural economy that has otherwise largely disappeared from the Connacht countryside.

The details of when this particular mill was built, who operated it, and when it finally fell out of use remain, for the moment, unrecorded in any publicly accessible form. What can be said is that Oghil More sits in a part of Galway where small milling operations served dispersed rural populations through the eighteenth and nineteenth centuries, often tied to the fortunes of local landlords or tenant farming communities. Many such mills declined sharply after the Famine years of the 1840s, as population collapse reduced the demand for local grain processing and larger commercial operations drew trade away from these intimate neighbourhood structures. Whether this mill followed that pattern is not yet confirmed, but the arc is a familiar one across the west of Ireland.