Yet the foundations of this early ecclesiastical site on a south-facing slope in north Clare survive just below the grass, their outline measurable at roughly fifteen metres east to west and eight metres wide, visible only through aerial photography. The very name of the place carries its own puzzle: Killaspuglonane derives from the Irish Cill Easpaig Lonáin, meaning the church of Bishop Lonán, and the question of who exactly that bishop was has occupied antiquarians for well over a century.

The site sits within an ecclesiastical enclosure, on rising ground with open views to the south and west, and was listed among early church-sites in north Clare by Sheehan in 1982. Its origins are traditionally placed around the sixth century. John O'Donovan and the historian Frost both equated the founding Bishop Lonáin with St Flannan of Killaloe, the seventh-century saint associated with the diocese that bears his name. Thomas Johnson Westropp, the Clare antiquary who documented the region's monuments extensively in the early twentieth century, disagreed, arguing instead that the founder was a distinct figure, a Bishop Lonan who was a friend of St Maccreiche, to whom a nearby holy well is dedicated, and whom Westropp placed at around 550 AD. Whatever the founder's identity, the church was functioning as a parish church into the later medieval period. In 1302 to 1306 it was valued at 26 shillings, a valuation it shared with several other churches in the diocese of Kilfenora. By the time of the Royal Visitation of Killaloe in 1615, however, it was already described as ruinated, and by around 1814 the writer Mason was recording only the ruins of the church attributed to Bishop Lenane. Within a generation of that observation, O'Donovan noted that it had been entirely levelled.

What remains visible on the ground today is largely fragmentary and requires some patience to read. The grassed-over foundations lie just inside a roadway running northwest to southeast, roughly 28 metres southeast of the present graveyard. Dressed stone that likely came from the church itself can be found incorporated into the graveyard wall, repurposed at some point after the building's collapse. A smaller, unidentified structure lies approximately 16 metres to the south of the church footprint, also detectable only from aerial imagery.