The site occupies low, marshy ground that would have been strategically positioned to overlook the seasonal lake. Today, visitors will find a grass-covered rubble mound measuring roughly 22 metres from north-northwest to south-southeast and 18 metres from east-northeast to west-southwest, rising to just over 2 metres at its highest point.

The castle mound forms part of a larger D-shaped enclosure that stretches approximately 64 metres from northeast to southwest. This defensive perimeter is still partially visible, defined by a fosse (defensive ditch) along its northwestern edge that measures 4 metres across at the top and narrows to about a metre at its base. A drainage channel runs along the southwestern boundary, though the southeastern and southern edges of the enclosure have been lost to time and can no longer be traced on the ground.

The history of this site remains somewhat mysterious. William McHugh Kelly owned more than 600 acres in Ballagh and Raharrowbeg in 1641, yet curiously, no castle appears on the Strafford map from around 1636, and written references to a fortification here are absent from historical records. The castle first appears on Ordnance Survey maps in 1837, leaving questions about its exact date of construction and whether it replaced an earlier structure. The lack of documentary evidence suggests this may have been a relatively minor fortification, perhaps built during the turbulent 17th century when local landowners frequently erected defensive structures.