The enclosure is roughly 37 metres across, its grass-covered interior ringed by an overgrown bank, a flat-bottomed fosse or defensive ditch, and beyond that an outer bank. The whole arrangement sits quietly in the landscape, most legible on the south-western to northern arc where the outer bank still rises to around two metres. It is the kind of feature that reads clearly once you know what you are looking for, but could easily be mistaken for a natural rise in the ground.

The identification with a castle goes back at least to around 1840, when the site was pointed out to John O'Donovan, the distinguished Irish-language scholar and antiquarian who spent years travelling the country documenting place names and local lore for the Ordnance Survey. What he was shown was understood by local people to be the location of Finshoge castle. Whether the earthwork and the castle are one and the same is not straightforward. The structure has since been classified as a possible ringwork castle, a type of fortification common in Ireland from the twelfth and thirteenth centuries, consisting of a roughly circular enclosure defended by an earth bank and ditch rather than a stone keep or a raised mound. The southern end of the enclosure may mark the original entrance. Adding further texture to the immediate area, another earthwork lies about 80 metres to the south, and a rath, the familiar circular bank-and-ditch enclosure associated with early medieval settlement, sits some 150 metres to the south-east, suggesting this valley floor has been occupied and modified across a long span of time.