It is, in fact, the remains of an early ecclesiastical enclosure, the kind of boundary that once marked out sacred ground from the secular world around it. These enclosures, common across early medieval Ireland, defined the territory of a monastic or church settlement, separating the spiritual community within from the farmland and trackways beyond. What survives at Castleturvin is modest, but the geometry of the thing, nearly 76 metres from north to south and 61 metres from east to west, gives some sense of the deliberate scale of the original layout.

The enclosure wall is double-faced drystone construction with a rubble core, a method that uses two parallel lines of stone with loose material packed between them, giving the wall both stability and some bulk. It stands between 0.3 and 1.7 metres high depending on where you measure, and survives best along its western and northern arc. The eastern sector has been cut by a modern gap of around 6.5 metres, and a field boundary has been laid directly over the wall from east to south-southeast, obscuring that stretch considerably. A roadway runs around the outside of the enclosure from the south through west to northwest, which may itself follow a much older path that once circled the site. Inside, in the southern half of the interior, a church and graveyard still occupy the ground, continuing a function the enclosure was presumably built to protect. Cody, writing in 1989, also noted a possible internal division in the south-east quadrant, a grass-covered stony bank that might indicate the enclosure was once subdivided into distinct zones, as was sometimes the case in more complex early church settlements.

The enclosure is on private pastureland, and the surrounding road offers the clearest view of the surviving western and northern wall. The inner face of the wall is easier to read than the outer in places where modern activity has disturbed it, and the slight curve of the bank becomes more legible once you know what you are looking at.