The enclosure measures some 63 metres across, making it a substantial feature, the kind that would once have organised and dominated the land around it in ways that are now difficult to read precisely.

Earthen enclosures of this type are among the most common yet least understood monuments in the Irish countryside. They were formed by raising a bank of soil and earth around a defined area, and they served a range of purposes across different periods, from early medieval settlement and agriculture to stock management and territorial marking. What makes the Lisnaminaun example quietly interesting is not just its size but the additional earthworks around it. Several low banks radiate outward from the main enclosure to the west, north, and north-east, and while their relationship to the central monument is not certain, they suggest the site was once part of a more elaborate arrangement of activity on the ridge. The main bank has been breached in several places by cattle gaps, openings made by farmers moving livestock through the monument over many generations, which is a very common form of gradual, incremental alteration to these sites across Ireland.

The position itself is telling. Ridge summits overlooking low-lying or waterlogged ground were frequently chosen for enclosures, partly for drainage and visibility, and partly because the marshy land below was often less suitable for settlement or tillage, making the higher ground the practical and perhaps socially prominent choice.