What remains today is the square bawn, measuring 75 metres east to west and 70 metres north to south, with walls a metre thick. Of the original four corner towers, only the southeast and southwest examples survive, each displaying an intriguing architectural quirk; whilst their interiors are perfectly circular, their exteriors feature angular projections facing outward from the bawn. These three-storey towers were accessed via external wooden staircases within the courtyard, with each level having its own doorway. The first floor of one tower still retains a fireplace with punch-dressed jambs and drafted margins, though most other doorways have been destroyed over time.

The defensive features of Kilcolgan reveal its strategic importance during turbulent times. A machicolation and rectangular chimney stack on the south wall’s first floor level may be all that remains of the original fortified house, with the machicolation possibly protecting an entrance to the main building. The bawn’s original entrance was located at the eastern end of the north wall, now destroyed, but once bore a date stone from 1649. This date aligns with the castle’s moment in history when it hosted the Papal Nuncio Rinuccini in 1648 during his journey from Kilkenny to Galway, marking it as a significant stronghold of the Mac Coghlan family during the Confederate Wars.

The true tragedy of Kilcolgan came in the 1950s when the Electricity Supply Board demolished the fortified house for rubble to construct a nearby power station, destroying what photographs from the architectural archive reveal was an impressive L-plan building. This two-storey structure featured a crenellated wall walk, Jacobean chimney stacks, and elegant transomed and mullioned windows; a fine example of mid-17th century Irish castle architecture now lost forever. Today’s visitors must use their imagination to picture the complete defensive complex that once dominated this gently rolling landscape, though the surviving bawn walls and towers still offer compelling evidence of the site’s former importance.