It looks, at first glance, like nothing more than an overgrown field anomaly. It is, in fact, the remains of a rath, the Irish word for a ringfort, the most common archaeological monument type in the Irish countryside. These were enclosed farmsteads, typically dating from the early medieval period, roughly the fifth to the twelfth centuries, built by farming families who raised an earthen bank or, in stony areas like much of Cork, a stone wall around their dwelling and animal enclosures.

The Lettergorman example is of the stony variety, its circular form still legible despite centuries of neglect. The diameter of thirty-five metres puts it within the typical range for a single-family enclosure, neither unusually large nor especially small. What makes it quietly notable is the way the landscape has moved in around it: the thistles forming their own accidental boundary, the ferns filling what was once a defined interior. The break in the slope on which it sits would have offered some natural shelter from the north, a practical consideration for whoever chose this spot to build and live, likely over a thousand years ago.