The 1655 Down Survey map of Newtown parish depicts it as a castellated house complete with gable-ended chimneystacks and a lower house extending from one side. At that time, the castle stood on lands belonging to Thomas Geoghegan, recorded as an ‘Irish papist’ in the survey documents. The parish map’s terrier went so far as to describe it as a ‘handsome House at Cominstowne’, suggesting it was a structure of some significance in the local landscape.

The castle’s history is intertwined with the tumultuous events of 17th-century Ireland. Thomas Geoghegan of Cominstown appears in records from 1653-4 as one of the people transplanted from County Westmeath, part of the Cromwellian policy that forcibly relocated Catholic landowners. By 1837, when the Ordnance Survey Letters were compiled, the castle had already fallen into ruin, with surveyors unable to gather any information about when it was built or by whom. The Ordnance Survey maps from 1837 and 1910 show it as a rectangular building oriented northeast to southwest, with additional structures to the north-northeast and south-southwest.

Today, no trace of Cumminstown Castle remains visible above ground. When assessed in 1973, researchers found that the castle had been completely levelled, with a modern house built on the site. Even aerial photography reveals nothing of the former stronghold that once stood proudly on this ridge, its story preserved only in historical documents and maps; a reminder of the dramatic changes that swept through the Irish countryside during and after the Cromwellian period.