A mill race is a man-made watercourse, cut or embanked to direct the flow of a stream or river onto a waterwheel with enough force to grind grain, full cloth, or drive some other machinery. Their presence in the landscape, even when the structures above ground have long since collapsed or vanished, tells a quiet story about how rural communities organised their labour and their water.

Unfortunately, the available documentation for this particular site is too sparse to say more about its age, its builder, or the period during which it was in use. What can be said is that mills and mill races of this kind are a common feature of the Irish rural landscape, many of them dating from the eighteenth or nineteenth centuries when landlord estates and improving agricultural schemes encouraged their construction across Connacht. Others are considerably older. The survival of even a fragmentary mill race as a recognised monument suggests the earthworks or cut at Gortnaraha remain legible in the ground, worth enough to record even if the full story has not yet been told.