Ringforts, sometimes called raths, were typically enclosed farmsteads of the early medieval period, their earthen banks and ditches defining a household's domestic space. What survives at Carrowbaun is essentially the eastern half of one such enclosure, the western two-thirds having been levelled at some point between the first mapping of the site in 1838 and the present day. The 1838 OS six-inch map recorded a complete circular embanked enclosure; by 1916, only the D-shape remained, its straight eastern edge formed by a north-south field wall that doubles as both a townland and a property boundary.

The surviving portion is still legible on the ground. A raised D-shaped platform, roughly 16 metres north to south and just over 9 metres east to west, is defined on its curving western side by a pronounced earthen scarp about 1.5 metres high externally, with occasional stone showing through the sod. Beyond this scarp lies a broad, well-defined fosse, the ditch that originally encircled the entire rath, running to about 5 metres in width. Outside the fosse is a gravelly external bank, itself between 6 and 7 metres wide, rising to between 1.5 and 1.8 metres on the outer face. To the east of the dividing field wall, a low undulation in the pasture preserves the ghost of the levelled north-eastern quadrant; the south-eastern quadrant has left no trace at ground level at all. The site sits on a rise within undulating terrain, and the surrounding ridges create an effect of standing inside a shallow natural bowl, with Nephin mountain visible on the far western horizon. Within 350 metres to the south-west, a ringbarrow, a low circular burial mound of probable prehistoric date, sits on the skyline, and 175 metres to the north-east stands a cashel, a stone-walled enclosure of broadly similar function to the rath but built in drystone rather than earth.