What began as a 13th or 14th century hall house with a first floor entrance was later transformed into a tower house, likely during the 15th century or afterwards. The castle’s history can be traced back to at least 1641, when historical records from the Down Survey show the lands of ‘Ballistowne’ were held by James White. Today, the limestone rubble walls rise three storeys high from their distinctive base batter, which is crowned by a string course running 1.25 metres up from ground level.

The castle’s rectangular form, measuring approximately 9.7 metres northwest to southeast and 7.4 metres northeast to southwest, reveals intriguing architectural details that hint at its complex past. Entry is now through a round arched doorway in the northwest wall, though evidence suggests this may be a later addition; the original entrance was likely at first floor level in the southwest wall, where the remnants of an arched opening and protruding tie stones indicate a possible stone forebuilding once protected the entrance. The ground floor features a barrel vaulted chamber standing 3.8 metres high, lit by narrow slit windows and equipped with several wall cupboards or aumbries for storage, all still bearing traces of well preserved render.

Aerial photographs from 2011 reveal the ghostly outline of what may have been a rectangular bawn, or defensive courtyard, surrounding the castle on its low platform. At the northern corner of this platform, a slightly raised area suggests the possible remains of an angle tower, adding another layer to the site’s defensive capabilities. Though parts of the structure have collapsed, particularly the western angle of the southwest wall and much of the northeast wall, the castle remains an evocative monument to medieval life in Westmeath, its walls standing testament to centuries of Irish history and the changing fortunes of those who once called it home.