By the time of the Down Survey, this once formidable stronghold had already fallen into ruin, though its impressive structure still stands today as a testament to medieval Irish tower house architecture. The rectangular tower, measuring 12.5 metres northeast to southwest and 9.4 metres northwest to southeast, rises five storeys high and features the characteristic base batter and wall walk typical of defensive structures from this period.

The castle’s interior reveals the sophisticated planning that went into these fortified homes. A spiral staircase tucked into the eastern corner connects the different levels through two centred arched doorways, whilst the northern corner houses a guard chamber; a strategic placement for monitoring who entered the tower. The fourth floor boasts a barrel vault running the length of the structure, with mural passages built into the southwestern wall on both the third and fourth floors, allowing defenders to move unseen through the building. The tower’s defensive capabilities are evident in its twenty seven narrow loops, some cross shaped, along with gun loops positioned in the eastern corner, showing how the castle was adapted for firearms as warfare evolved.

What makes Clonburren particularly interesting is the contrast between its military and domestic features. Whilst the lower levels maintained their defensive character with simple slit windows, the fifth storey served as the state room, illuminated by four elegant ogee headed windows, each divided by a mullion. The third and fourth storeys contained fireplaces, with the third floor featuring an ornamental chimney piece, now partially destroyed. A garderobe chute in the northeastern wall provided basic sanitation, whilst a machicolation that once ran around most of the top allowed defenders to drop objects on attackers below. Today, though roofless and weathered by centuries, the castle’s seven foot thick walls continue to stand, preserving this remarkable example of an Irish tower house that once served as both fortress and aristocratic residence.