The ground here was once carefully managed water, a mill pond engineered to store and direct flow to a working mill. Today the infrastructure is long gone, but the landscape itself retains the logic of its former purpose, the low-lying, waterlogged character of the land being less a product of neglect than of centuries of accumulated drainage and silting around a site that was once genuinely industrial.

The Civil Survey of 1654 to 1656, a detailed inventory of Irish land compiled in the aftermath of the Cromwellian wars, records a mill pond at a place then written as Reynoldstowne. The survey is a remarkable document, capturing landholding and land use at a moment of enormous political upheaval, and its mention of the mill pond here is one of the few specific records to survive for this site. The mill itself was not on the Dublin side of the county boundary at all; it sat in Tullog, County Meath, the pond and the mill separated by the invisible administrative line that runs through this stretch of river country. Both places, however, shared the same landlord in an earlier era. These lands had formed part of the monastic estate of St Mary's Abbey, the Cistercian foundation in Dublin that, before the dissolution of the monasteries in the sixteenth century, held extensive rural properties well beyond the city. A mill pond feeding a Meath mill from Dublin land was not unusual for a large monastic holding; such estates were managed as working economic units across considerable distances.

The site is not signposted or formally presented, and visitors approaching from the road will find little to mark it beyond the bridge and the river. The marshy ground to the south of the road is the main visible remnant, and reading it requires some patience and a reasonable idea of what a managed mill pond would have looked like, essentially a contained body of water, often embanked, positioned to release a controlled head of water to drive a mill wheel downstream. The Delvin river itself forms the boundary between County Dublin and County Meath at this point, which gives the crossing at Old Mill Bridge a quiet geographical significance. Wellington boots are advisable if you intend to explore the wet ground closely, and the drier months will make the approach more straightforward, though the marshy character of the enclosed area is likely to persist in most seasons.