It is the kind of place that registers as a slight swelling in a field before the eye adjusts and recognises the deliberate geometry beneath. The enclosure measures roughly 37.5 metres across its longer axis, defined by an earthen bank and an outer fosse, which is essentially a ditch dug to reinforce the bank's defensive profile. A second outer bank curves around the southern and eastern arc of the site. The entrance gap, about 2.5 metres wide at its base, faces south-east.

This type of earthwork is broadly classified as a ringfort, the most common monument type in the Irish countryside, built and used across many centuries but most associated with the early medieval period, roughly 500 to 1200 AD. They served as enclosed farmsteads for families of some local standing, the bank and fosse offering protection for livestock and household rather than military fortification in any formal sense. What makes Drumlane worth pausing over is less what survives than what has been lost. By 1995 a considerable portion of the western, northern, and southern perimeter had already been removed, most likely through agricultural land clearance. The earthwork recorded in the Archaeological Inventory of County Monaghan in 1986 was already a diminished version of what once stood. Archaeological testing carried out in 2000, when a water pipe was being laid roughly 50 metres to the north, turned up nothing connected to the monument, which at least confirms that its immediate surroundings have not yielded obvious associated activity at that distance.