In the northern quadrant of Ballysimon graveyard, where cartographers once drew the outline of a medieval parish church, there is now only grass, headstones, and whatever lies beneath the soil. It is the kind of absence that rewards a second look, precisely because the maps insist something was once there.

The church served the medieval parish of Derrygalvan, a place-name that shifted in spelling across the centuries as scribes and administrators rendered it phonetically. The antiquary T. J. Westropp, writing in 1904 and 1905, traced references to it as far back as 1291, when it appeared in records as Derigavun, then as Dalgarvun in 1302, and as Derighealvain in 1410, by which point it was recorded as being dedicated to St. Nicholas, whose feast day falls on the sixth of December. At some point in the fifteenth century the character of its dedication appears to have shifted; the rectory was granted to John, Abbot of Wethnia, the house known today as Abington or Abbey Owney, under the name of the Church of the Blessed Virgin. The building was significant enough to be recorded on the seventeenth-century Down Survey, a large-scale mapping project carried out in the 1650s to document land ownership across Ireland. By 1840, however, the Ordnance Survey field officers were already struggling to make much of it. Their notes record only small fragments of walling visible among what they called luxuriant weeds, and they concluded the remains were not distinct enough to give any idea of the extent or characteristics of the building.

The graveyard at Ballysimon remains in use, so the site is accessible in that sense, though there is nothing structural to examine once you arrive. What makes the visit worthwhile is the layering of evidence across time: the medieval dedications, the seventeenth-century cartography, the frustrated Ordnance Survey description, and the complete absence of masonry today. Roughly fifty metres to the north-east lies Ballysimon Well, a holy well that shares the townland name and adds another thread to the site's longer religious geography. The well is the more tangible of the two features now, which is itself a curious reversal.