The interior measures around 35 metres at its longest axis, enclosed by an earthen bank and a fosse, which is the outer ditch that would have made the enclosure defensible, or at least formidably inconvenient to enter uninvited. That fosse survives in its clearest form along the northern, southern, and south-south-western arc, where the ground has been less disturbed by farming or drainage work over the centuries.

The site belongs to a class of monument known as a rath, the most common type of enclosure in early medieval Ireland, typically associated with farming settlements of the period between roughly the fifth and twelfth centuries. A rath usually comprised a circular bank and ditch surrounding a homestead, housing a single family and their livestock. At Drumcrow, the original entrance can still be identified on the east-south-eastern side, where a causeway crosses the fosse and meets the bank, a detail that survives with unusual clarity. A stream runs immediately to the north of the site, a practical consideration that would have mattered greatly to whoever chose this location, providing water without placing the settlement on low or flood-prone ground. To the south, a well is recorded, though it has since been infilled.