Known as Our Lady's or St Mary's, it sits within its own square enclosure, slightly apart from the busier monastic core, and the prevailing theory is that it may have been built specifically for women or nuns, making it a rare example of a deliberately gendered ecclesiastical space within an Irish early medieval monastery.

The church has been partly restored, and its chancel contains two decorated cross-slabs, flat stones carved with cross motifs that were common markers of devotion and burial in early Christian Ireland. The wider graveyard holds a number of what are described as rude crosses and cross-slabs, meaning roughly worked or unfinished examples rather than the more elaborate high crosses associated with prestige sites. These modest stones are easy to walk past without registering what they are. The site overlooks the valley of the Glenealo River to the south, with the Lower Lake of Glendalough visible to the south-west, a setting that would have framed the daily life of whoever worshipped or lived here.