The trees were planted inside a ringfort, one of those circular enclosures, usually dating from the early medieval period roughly the fifth to twelfth centuries, that once served as farmsteads or high-status residences across the Irish countryside. There are tens of thousands of them recorded across Ireland, yet each one carries its own particular arrangement of earthworks, and this one at Ballyvaloon is a fairly well-preserved example of the double-banked variety.

The enclosure is almost circular, measuring 33.4 metres east to west and 32 metres north to south. It is defined by two concentric earthen banks with a fosse, or ditch, between them. A fosse is simply a defensive ditch, dug to reinforce the barrier created by the bank thrown up from its excavation. The inner bank stands to an internal height of 1.4 metres, while the outer bank reaches a maximum height of 2.1 metres. A second, outer fosse, surviving to a depth of 0.35 metres, is still traceable to the south. The entrance, about 4.5 metres wide, faces roughly south-southeast and retains its causeway across the fosse, the original approach to whoever lived and worked within these banks. Smaller gaps in the banks to the east may represent later breaches rather than original openings. The double-bank arrangement suggests this was a site of some local importance; a single bank was sufficient for most ringforts, and the extra earthwork indicates either greater defensive concern or a desire to signal status.