Historical maps from 1657 show the castle positioned in the northern section of the townland, just south of where the boundary with Rahardelin (now Ardillon) forms a distinctive U-shaped curve near an ancient ringfort. The Down Survey terrier from that same year confirms its presence, noting simply that “upon Catherinstowne stands a Castle.”

In 1641, the castle and its surrounding lands belonged to Thomas Tirrell, recorded in the Down Survey as an “Irish Papist”; a designation that would have significant implications for land ownership during this turbulent period of Irish history. By the time the Ordnance Survey mapped the area in 1838, the castle appears to have already fallen into ruin, with only a cluster of buildings shown north of the ringfort possibly marking its former location. The site has been somewhat confusingly catalogued in the Westmeath Record of Monuments and Places under an incorrect reference number (WM026-035).

The castle’s stones found new life in 1853 when they were reportedly used to construct the Roman Catholic Church at Gainestown, which now houses the historic Lynn Font. This repurposing of medieval masonry for nineteenth-century ecclesiastical architecture was a common practice throughout Ireland, transforming defensive structures into places of worship as communities rebuilt following centuries of upheaval. Today, visitors to the church can see these weathered stones, silent witnesses to the area’s layered history from medieval fortress to Victorian church.