The original castle structure forms the heart of the modern house, its thick stone walls measuring approximately 9.5 metres in length and 6.5 metres in width, with walls an impressive 1.5 metres thick and featuring the characteristic base batter typical of defensive architecture from this period.

This castle holds particular historical significance as the stronghold mentioned in the Civil Survey, once belonging to James Goodman, who served as Provost Marshall in the Confederate army during the turbulent years of the 1640s. The Confederation of Kilkenny, which Goodman served, was the de facto government of Ireland during the Confederate Wars, making this site an important piece of the complex puzzle of 17th century Irish history.

Today, visitors to Lehaunstown Park can still trace the outline of the original tower house within the later dwelling, where medieval defensive architecture meets more recent domestic construction. The integration of the castle ruins into the later building represents a common Irish architectural practice, where ancient structures were repurposed rather than demolished, preserving these fragments of history within the fabric of newer homes.