According to the Down Survey of 1655-6, this modest fortification consisted of "a little Round Castle with a Bawne and some Cabbins", a typical defensive arrangement of the period where a circular tower was surrounded by a fortified courtyard wall (or bawn) and various outbuildings. The castle belonged to Garrett Blanchvile, recorded as an Irish Catholic landowner in 1640, during a turbulent period just before the Confederate Wars would reshape Ireland's political landscape.

Local historian William Carrigan, writing in 1905, placed the castle a few hundred yards south of Kilmodimogue Church, specifically in the haggard of what was then the recently abandoned Cody farmstead. A haggard, for those unfamiliar with Irish agricultural terms, was the enclosed area near a farmhouse where haystacks were built and stored. The castle likely occupied slightly elevated ground south of the farm buildings, a sensible defensive position that would have offered clear views across the surrounding countryside.

The Down Survey map, one of the first systematic surveys of Irish land ownership, captured Kilmodimogue at a pivotal moment in Irish history. Created in the aftermath of the Cromwellian conquest, these maps documented properties that would soon change hands as Catholic landowners like Blanchvile were dispossessed under the Act of Settlement. While the castle itself has vanished completely from the landscape, its ghost lingers in these historical documents; a reminder of the countless small fortifications that once dotted rural Ireland, most of which have left no physical trace beyond entries in old surveys and the memories preserved in parish histories.