Recorded on Ordnance Survey maps as Cahercarbery (Beg), the site gives the optical illusion of a cramped interior, not because it is especially small, but because the double rampart curves convex towards the land and runs along the crest of a high ridge, compressing the apparent space within when viewed from the approach.

A promontory fort of this type uses the natural defence of coastal cliffs on three sides, relying on man-made earthworks or stonework only to block the landward approach. At Cahercarbery (Beg), that blocking takes the form of two substantial parallel stone walls, each with a fosse, the old term for a defensive ditch, cut on either side. The outer wall stretches 64 metres across and stands 3 metres above the outer fosse, with a base width of 8 metres; the inner wall, just 3 metres behind it, rises to 2.8 metres above its own fosse. The engineering involved in laying that much stone along a coastal ridge, maintaining consistent dimensions across both walls, points to a community with both organisational capacity and a serious concern for defence. A low mound, roughly 6 metres wide and 1.2 metres high, sits outside the outer bank at the south-eastern sector, and there may be a further fosse beyond it, though no features survive inside the enclosure itself. The fort lies about half a mile south of a second promontory fort in the same townland, suggesting this stretch of coastline was once considered worth defending in some depth. C. Toal's North Kerry Archaeological Survey, published in 1995, provides the most detailed account of the site's dimensions and layout.