Situated in the northern section of a hollowed out cairn on the summit of Church Mountain are the foundations of a rectangular church (10.5 m x 7 m), and a holy well. Some cut stone, presumably from the church, is mixed with the cairn rubble.

Herity includes the site in his gazetteer of passage tombs, however, it is not clear whether the cairn ever served this function. Gough (1789) relates local tradition that the cairn was constructed in the 12thc., as a raised enclosure for the church which was on the main route from Old Kilcullen to Glendalough. Gough records that some of the flagstones of the road were still visible, and that these were similar to those of the pilgrims' road at Glendalough. The 18thc. plate reproduced by Gough shows the church in a ruinous condition. Details of pilgrimages to the mountain are recorded on Lammas Day until c.1798 (Manning 2002, 64).

The fragments probably belonged to the portal of the church. Their plainness is not surprising given the hardness of the stone.