Measuring 7.1 metres by 6.2 metres, this stone mound features a central altar that visitors once approached through a passage entering from the south. What makes this site particularly intriguing is the primitive stone cross crowning the cairn, a clear indication that early Christians adapted and sanctified what was likely a much older sacred space.

Just to the north-northwest of the cairn sits a smaller drystone structure, its walls still standing up to 65 centimetres high despite centuries of Atlantic weather. This rectangular building, measuring 3.4 by 2.5 metres, may have served as a shelter for pilgrims or perhaps housed a hermit monk who tended to the site. The careful construction of both structures suggests this was once an important place of worship and penance.

The site at Rann Na Cille represents a fascinating layer of Irish spiritual history, where pre-Christian and early Christian traditions merged. Such penitential stations were common throughout medieval Ireland, serving as places where the faithful could perform acts of devotion, often involving prayer circuits around the cairn or time spent in contemplation at the altar. The combination of the ancient cairn, the later Christian cross, and the adjacent structure creates a unique archaeological ensemble that speaks to centuries of continuous sacred use.