What was once a defined earthwork, with a bank of earth and stone encircling a roughly rectangular space, survives today only as a trace visible on aerial photography, the kind of ghost that reminds you how much of the Irish landscape has been quietly erased.

When the monument was formally described in 1978, it measured approximately 52 metres north to south and 23 metres east to west, a subrectangular enclosure bounded by a low bank and an external fosse, which is simply a ditch dug around the outside of an earthwork as a boundary or defensive feature. The bank was most legible along the northern, eastern, and southern sides, with the fosse visible to the east and south-east. A shallow fosse also ran along the interior of the bank at the south-west, an unusual detail that complicates any simple reading of the site. In the southern sector, an L-shaped bank with a shallow fosse on its northern side has been interpreted as a possible house site, suggesting that the enclosure was not merely a field boundary but may once have contained domestic activity. A wide, low bank extends outward from the monument to the north-north-west, hinting at further organisation of the surrounding land. A depression in the northern corner appears to be the result of more recent quarrying rather than anything older.

The site sits on a slope that opens up views to the south, west, and north, while the eastern aspect is restricted. That positioning, commanding a broad outlook across three compass points, is a recurring feature of early enclosures in Ireland, where elevation and visibility often guided where people chose to settle and demarcate space. What survives at Dunnamona is minimal by any measure, but its faint geometry, readable only at a remove, is quietly eloquent about how thoroughly ordinary life can be subsumed into a hillside.