A circular enclosure roughly twenty metres in diameter was recorded here, its outline captured on the first edition of the Ordnance Survey six-inch map, that meticulous mid-nineteenth-century cartographic project that swept across Ireland and committed to paper thousands of features, earthworks, and field boundaries that surveyors on horseback could still observe. Today, no visible surface trace of the enclosure survives.

Circular enclosures of this kind are among the more common archaeological features in the Irish landscape, typically associated with the early medieval period, though their functions varied considerably. Some enclosed farmsteads, known as raths or ringforts, defined by an earthen bank and ditch. Others had ritual or burial purposes. Without excavation, it is rarely possible to say which a particular example was. What can be said of the Cill Ogúla site is that the name itself carries meaning: "cill" in Irish generally refers to a church or monastic cell, suggesting the area may have had ecclesiastical associations at some point in its past, though the enclosure's direct relationship to any such function remains unestablished. The site appears in Paul Gosling's Archaeological Inventory of County Galway, published in 1993, which remains one of the more thorough regional catalogues of its kind for the west of the county.

What makes the site quietly interesting is precisely what it illustrates about the limits of surface evidence. The first edition OS map recorded something that the landscape no longer shows. Whether it was ploughed out, built over, or simply eroded away is unknown. The map becomes the monument.