Rathandarris appears on Ordnance Survey maps from 1838 onwards, its oval outline recorded with enough care that later generations could at least know what had been lost. A rath is a roughly circular or oval earthen enclosure, typically dating from the early medieval period and associated with a farmstead or minor settlement, defined by one or more banks and ditches. By the time the 1922 six-inch map was made, Rathandarris measured approximately 22 metres east to west and 27 metres north to south, though even then a straight field boundary had already cut into its southern and south-western edge.

What the maps could not prevent was what came afterwards. The rath has since been levelled entirely, and the north-eastern and eastern quadrant have been quarried away, leaving a steep scarp that drops directly into the adjacent farmyard. It is a pattern seen at many such sites across Ireland, where the convenience of ready-made elevated ground and loose material proved more immediately useful than the earthwork itself. The name Rathandarris, with its Irish-language root in "rath", preserved in place-name records long after the physical form ceased to exist. A second rath survives roughly 200 metres to the north-west, which gives some sense of how this landscape was once organised, with enclosed farmsteads placed at intervals across rising ground.