Historical records show that John Fleming of Siddan owned 500 acres here, including the castle, around 1640. The structure appears to have already fallen into ruin by the time of the Down Survey in 1656-8, which depicts two derelict buildings at Suddan; one of these ruins corresponds with this location. The barony map from that period includes Polecastle within the bounds of Siddan, providing a clear link between the Fleming estate and this defensive structure.

The castle's position, just south of the old road connecting Ardee to Kells, made it strategically important for controlling movement through this part of Meath. Taylor and Skinner's 1793 map shows two ruins at Suddan south of this ancient route, with one structure positioned near the river to the south, which aligns with the current site. By the 19th century, the Ordnance Survey maps of 1836 and 1908 simply recorded it as the 'Site of Old Castle', suggesting that little remained of the original structure even then.

Today, visitors will find an irregularly shaped mound approximately 18 metres in diameter and rising about 60 centimetres above the surrounding landscape. While it may not look like much to the casual observer, this unassuming earthwork represents centuries of Irish history; from medieval fortification to landed estate, and eventual abandonment. The site serves as a reminder of how the Irish landscape is layered with the remnants of past lives and lost buildings, many of which survive only as subtle changes in the topography and entries in old maps and surveys.