A killeen, sometimes spelled cillin, was a marginal burial place used in Ireland for centuries to inter those who could not, under Catholic Church practice, be laid to rest in consecrated ground: unbaptised infants, stillborns, and occasionally suicides or strangers. These sites occupy a particular kind of ambiguity in the Irish landscape, neither fully sacred nor fully secular, and the one at Ballyconry in County Kerry is a quietly substantial example of the type.

The mound itself is elongated and roughly sub-rectangular, running to 21.6 metres in length, between 4 and 7 metres wide, and rising to 1.5 metres at its highest point. Those are not insignificant dimensions, and they suggest long use rather than a brief or incidental history. A fieldbank runs along the western edge of the site, sitting less than 2 metres away. Towards the centre of the mound on the southern side, there is a disturbance, a narrowing of the mound to around 4 metres, though its cause is not recorded. C. Toal's North Kerry Archaeological Survey, published in 1995, provides the physical description of the site, placing it within the broader pattern of such burial grounds across the region.