A low, broad bank runs south from the southwest corner of the castle ruins, extending until it meets a wide ditch that runs northwest to southeast. This ditch could potentially be a fosse, a type of defensive moat commonly found around medieval fortifications in Ireland.

The possible fosse stretches from the modern field fence southwest of the castle to a point south of the castle, where it appears to turn northward towards the farmyard. These earthworks; the bank and fosse; might have formed part of the castle's original defences or perhaps enclosed a bawn, the fortified courtyard typical of Irish castle complexes. However, the presence of post-1700 farmyard buildings makes it challenging to determine their exact purpose and extent with certainty.

The site has undergone considerable change over the centuries. The post-1700 farmyard that once occupied the area has since been replaced by a modern dwelling house, adding another layer to the complex history of this location. Despite these alterations, the earthworks remain visible, offering tantalising hints about the medieval defensive landscape that once protected Balleagny Castle and its inhabitants.