The Irish name translates roughly as "the rough quarter", and it is the kind of place where the ground itself tends to tell more than any official record currently can. Settlement clusters of this type are groupings of related archaeological features, typically the foundations of houses, field boundaries, and enclosures, that together suggest a community once organised its daily life around a shared piece of ground. In the west of Ireland, such clusters often date from the medieval period or earlier, though many were reoccupied and abandoned repeatedly across the centuries, their layers of use compressed into low earthworks that are easy to overlook.

An Cheathrú Gharbh lies in Mayo, a county whose archaeology ranges from Neolithic field systems at the Céide Fields to post-medieval rundale settlements abandoned during and after the Famine years of the 1840s. Without more specific detail currently available for this particular cluster, it is difficult to say with confidence which period its remains belong to, or what form they take on the ground. What is certain is that the name of the townland itself carries meaning: townland names in Irish-speaking or formerly Irish-speaking areas of Connacht frequently preserve observations about terrain, land quality, or the character of a place as it was understood by the people who farmed it. A rough quarter suggests marginal land, the kind that communities nonetheless made work when more fertile ground was unavailable or already occupied.