What the road layout is actually following, however, is the ghost of a roughly circular early ecclesiastical enclosure, around 260 metres across, whose boundary has been absorbed so thoroughly into the field system that it now presents itself as a thorn hedge, a stream, a low earthwork, and a stretch of stone-and-earth bank, each segment belonging to a different field, each quietly completing the same ancient arc.

The townland name, Cill Easpaig Lonáin, means the church of Bishop Lonán, and the identity of that bishop has kept antiquarians busy for well over a century. John O'Donovan and the historian James Frost both argued that the Lonáin in question was St Flannan of Killaloe, the seventh-century bishop venerated across the diocese that still bears his name. Thomas Johnson Westropp, writing in 1910, was unconvinced; he proposed instead a Bishop Lonán described in early sources as a companion of St Maccreiche. The enclosure itself was formally identified as an ecclesiastical site by the researcher L. Swan in 1987, the same year Swan published a study of the carved stone head found near the holy well just east of the enclosure, an object now held in the National Museum. The grassed-over remains of a later medieval parish church lie towards the southern extent of the enclosure, alongside the footprint of another building and a trapezoidal graveyard to their north-west. The site occupies the steep south-facing slopes of Knockatemple, a ridge whose name, combining cnoc (hill) and teampall (church or temple), quietly confirms that people have been reading this landscape as a sacred one for a very long time.

The enclosure is most legible from the field boundaries themselves rather than from any standing structure. The northeast quadrant, named simply "Glebe" on the 1840 Ordnance Survey six-inch map, is where the thorn hedge follows the old line most clearly. The northwest quadrant has left no visible trace. The marshy ground to the south softens the southwestern arc into something more suggested than defined, which is perhaps the appropriate register for a site whose founding bishop cannot quite be pinned down either.