Beneath or immediately around an ordinary domestic plot lies what was once a circular embanked enclosure, the kind of feature found scattered across the Irish countryside and typically associated with early medieval settlement. These ringforts, as they are broadly known, were formed by a raised bank of earth and stone enclosing a central living or farming area. At Tonroe, local information confirms that the bank was indeed of earth and stone construction, though nothing of it now remains.

The enclosure was already being mapped by the mid-nineteenth century. The Ordnance Survey six-inch map of 1838 recorded it as a circular feature roughly 25 metres in diameter. By the time the 1920 edition was produced, it appeared slightly larger and somewhat irregular in outline, running approximately 30 metres on the northwest to southeast axis and between 25 and 30 metres across the northeast to southwest. That later map also shows a trackway skirting the southern side of the enclosure, leading eastward to two vernacular buildings positioned just beside it, suggesting the site was still a recognisable landmark in the local landscape even as the twentieth century began. At some point after that, the enclosure was destroyed entirely, its bank levelled and the ground built over. No physical trace survives above the surface today.