The platform, roughly 26.5 metres across, rises about 45 centimetres above the surrounding field, ringed by a V-shaped fosse, that is, a defensive ditch cut into the ground, and an external earthen bank that stands a metre high on both its inner and outer faces. What is slightly unusual here is that the bank actually rises higher than the platform it encloses, which inverts the expectation a visitor might bring to such a site.

This is almost certainly a ringfort, the most common class of early medieval monument in Ireland, typically dating from roughly the fifth to the twelfth century. Ringforts served as farmstead enclosures, the bank and fosse forming a boundary that kept livestock in and opportunistic raiders out. Most surviving examples are defined by a single earthen rampart, though the proportions at Ballywalter, with its substantial external bank and clear fosse, suggest something reasonably well-preserved beneath the vegetation. There is a break in the bank to the south-south-east, which would likely mark the original entrance. On the northern side, the bank has become absorbed into the existing field boundary system, a fate common to many such monuments, as later agricultural generations found it convenient to press old earthworks into service as ready-made divisions between fields.