This fortified tower house, built sometime before 1640, appears on historical parish maps from the Down Survey of 1656-8, though curiously absent from the corresponding barony map of Fore. The castle’s story is pieced together through fragments of documentary evidence; the Civil Survey of 1654-6 reveals it was owned by Richard Plunkett of Loughcrew, who held nearly 120 acres at Garclonne including the castle, described as being in “indifferent good repair”, alongside seven small cabins.

By the time Ordnance Survey cartographers arrived in 1836, Green Castle was already showing its age, depicted amongst a cluster of buildings and marked in gothic lettering on their six-inch maps. The later 25-inch survey maps from the Victorian era show it had been reduced to a shell, measuring roughly eight metres north to south and five metres east to west; modest dimensions that suggest this was likely a typical Irish tower house rather than a grand fortress. The Plunkett family connection places it within the network of Anglo-Norman settlements that dotted this part of Meath, serving as both defensive structures and symbols of authority in the Irish midlands.

Today, no visible traces of Green Castle remain above ground, its stones likely incorporated into later buildings or cleared for agriculture. The site represents countless similar small castles across Ireland that have vanished from the landscape, known only through historical records and old maps. These modest fortifications once formed the backbone of local power structures in medieval and early modern Ireland, housing minor gentry families who controlled the surrounding farmland and collected rents from tenant farmers in those clusters of cabins mentioned in the Civil Survey.