The graveyard enclosure, roughly a hundred metres long and forty metres wide, is notably uneven, its interior ground raised by as much as two and a half metres along much of its length. This is most likely the result of the masonry perimeter walls being built up and the excavated material thrown inward, so that the dead rest on ground that is partly of the wall-builders' own making. Headstone inscriptions recorded here run from 1722 to around 1900, a relatively recent span for a site with a much deeper history.

The place is dedicated to St Aodhán, son of Aonghas, a figure connected to the Ceinéal Eichin branch of the Cinéal Eoghan of Donegal, about whom remarkably little is known beyond his lineage and his feast day, the 2nd of November. By the early fourteenth century the site was already functioning as the parish church of Kilmore, recorded under the name Celmor alongside the chapel of Drumsnat in the ecclesiastical taxation of Pope Nicholas IV, drawn up between 1302 and 1306. Clergy serving here are named in records from 1424, but by 1622 the medieval fabric had deteriorated badly enough that Bishop Spottiswood described the church as ruinous. The present building replaced it in 1790, constructed as the Church of Ireland Church of St Aidan, and it remains in use today.

The sole physical trace of the medieval church is a bullaun stone, partly buried near the northern inner edge of the graveyard perimeter. A bullaun is a large stone with one or more artificial depressions or basins hollowed into its surface, found at early ecclesiastical sites across Ireland and often associated with ritual or curative use. This one is sandstone, flat-topped and roughly D-shaped, measuring about 0.85 metres by 0.8 metres, with a single basin approximately 38 centimetres across and just under ten centimetres deep. It is not dramatic to look at, being mostly buried and easy to overlook, but it is the one object on the site that reaches back before the post-medieval collapse and rebuild, a quiet residue of whatever stood here in the centuries when Aodhán's feast day was still being marked in November.