From the outside it reads as little more than a gentle rise in the ground, but the structure is precise: a circular mound, a surrounding ditch, an outer bank, and a narrow causeway on the eastern side that provides the only formal way in. That causeway, just 1.8 metres wide, is the detail that shifts the whole thing from natural feature to deliberate architecture.

A ring-barrow is a burial monument of the prehistoric period, typically consisting of a central mound enclosed by a circular ditch, called a fosse, and an outer bank. The one at Drom measures 17 metres across its external diameter on the north-south axis. Its central mound averages about half a metre in height, while the surrounding fosse runs 1.8 metres wide and drops half a metre deep. The outer earthen bank rises to a metre on its inner face and 0.8 metres on its outer face. At the centre of the enclosed interior there is a depression measuring roughly 0.75 by 2.3 metres, with some stones visible within it. That hollow almost certainly marks the location of the original burial, the point around which the entire structure was organised. The site is recorded in C. Toal's North Kerry Archaeological Survey, published in 1995, which documented monuments across this part of the peninsula and brought a number of quietly significant sites like this one into clearer focus.