The enclosure measures around 61 metres north to south and 41 metres east to west, and while that is not a large area, the arrangement of what lies within it, and immediately outside it, gives the site a quiet complexity that a casual glance across the pasture would not reveal.

Ecclesiastical enclosures of this type were the defining spatial feature of early Irish Christianity. A bank, a fosse (that is, a ditch cut into the ground outside the bank), and a formal entrance together marked out sacred ground from the secular world around it. At Ballynakill, the external fosse is still traceable from the south-east around to the south, and a possible entrance survives at the south-south-east. The southern half of the interior is occupied by a church and graveyard, suggesting that Christian use of the space continued long after whatever community first laid out the enclosure had disappeared. What complicates the picture further is a ringfort sitting roughly 50 metres to the south-south-east. Ringforts were typically secular homesteads of the early medieval period, formed by a circular earthen bank enclosing a farmstead, and their proximity to ecclesiastical enclosures is not unusual in the Irish landscape. Whether this one predates the religious site, postdates it, or belonged to a family with some formal association with it, the notes do not say, but the pairing is a recurring feature of early Christian settlement patterns across the country.

The site is set in ordinary working pastureland, and much of the enclosure boundary is poorly preserved, which means the full oval outline is not immediately readable on the ground. The church and graveyard in the southern interior are the most legible elements, and it is largely through them that the earlier enclosure beneath and around them can be understood.