That near-invisibility is itself worth pausing over. This is a rath, the most common type of early medieval enclosed settlement in Ireland, typically dating from roughly the sixth to the twelfth century. A rath is formed by a circular earthen bank, sometimes accompanied by a ditch, or fosse, dug on the outside. Thousands survive across the island, but the majority have been so altered by agriculture and drainage works that reading them on the ground requires a certain patience.

The Tulligmacthomas example is a roughly circular enclosure, measuring forty metres across in both its north-south and east-west axes. The surrounding bank still stands to an internal height of around 0.65 metres, and to an external height of 1.3 metres, with a fosse beyond it reaching some 2.3 metres in width and 0.45 metres in depth. Those figures were compiled by Denis Power and uploaded to the record in August 2011. Since that survey, a watercourse has been cut directly through the fosse, running from the south-west toward the north-east, which has introduced additional moisture to an interior already described as marshy pasture with patches of overgrowth. Within the northern half of the interior, a low linear ridge persists, roughly nine metres long and 2.6 metres wide, rising to about 0.45 metres. Its function is not noted in the record, and it sits there as a quiet puzzle within a quiet puzzle.

The site sits in ordinary farmland, and access, as with many such monuments on private agricultural ground in Ireland, depends on the goodwill of the landowner. The marshy interior and the recently cut watercourse mean that the fosse in particular may be wetter and less defined than the survey figures suggest, especially after prolonged rain. The bank is best appreciated by walking the perimeter, where the difference in height between internal and external faces becomes legible underfoot even when the eye struggles to distinguish it. The interior ridge, low as it is, is easier to spot from the bank than from ground level. It is the kind of place where the archaeology is present but undemonstrative, asking for a slow look rather than a quick one.