The site sits near the bottom of a south-east-facing slope, growing over with long grass managed for silage, scrub creeping in along the southern edge. It is the kind of place that continues to function as working farmland while something considerably older persists underneath.

The fort is subcircular in plan, measuring roughly 26.7 metres east to west and 23.7 metres north to south from crest to crest. A ringfort, sometimes called a rath, is a type of enclosed settlement built throughout Ireland during the early medieval period, typically between the fifth and twelfth centuries; most consisted of a circular earthen bank and ditch surrounding a farmstead or high-status dwelling. At Cahersherkin, the bank survives best along the northern and north-north-eastern arc, where it remains flat-topped, about two metres wide at the base and standing roughly 0.8 metres on its outer face. Moving around the circuit, it gradually diminishes to a scarp, and the section from the east-south-east has been further reduced by the farm traffic mentioned above. One of the more intriguing structural details is a stone-faced wall, 3.3 metres wide, that has been incorporated into the bank along the south-western to northern stretch, suggesting a later phase of construction or consolidation. An external drain runs alongside this section. There are two gaps in the bank: one at the north-east, around two metres wide, may be the original entrance; a wider gap at the north-north-east, measuring three metres, is likely a modern intervention. A shed and a disused quarry sit just to the north, completing the picture of a landscape that has been continuously worked and reworked around this much older structure.