The site features a gently sloping, flat-topped mound standing approximately 3.5 metres high, which would have once supported a wooden tower or keep. This mound sits within a distinctive D-shaped bailey, a fortified enclosure measuring roughly 62 metres east to west and 52 metres north to south.

The bailey itself is defined by a substantial flat-topped earthen bank, about 10 metres wide, which rises to 2.4 metres on its outer face whilst the inner height measures around 1.1 metres. This defensive earthwork encircles most of the site, though it’s notably absent at the northeast section. Whilst many motte and bailey castles featured a water-filled ditch or dry fosse around their perimeter for added protection, no evidence of such a feature survives at Srahanboy today, though one may have existed when the castle was actively defended.

These earthworks represent a type of fortification introduced to Ireland by the Anglo-Normans in the late 12th century. Motte and bailey castles were relatively quick to construct using local labour and materials, making them ideal for securing newly conquered territories. The wooden structures that once crowned these earthworks have long since vanished, leaving only the impressive earthen remains that continue to shape the landscape centuries after their military purpose ended.