The enclosure at Carrowroe measures roughly 37.5 metres north to south and 32.6 metres east to west, ringed by a bank of earth and stone that rises only between 0.2 and 0.5 metres at its highest point, with a width of around 4.7 metres. It is, in other words, a fort that has largely stopped looking like one.

This type of earthwork, broadly classed as a ringfort, was a common form of enclosed settlement in early medieval Ireland, typically used as a farmstead and defined by a circular or oval bank, sometimes accompanied by an external fosse, which is a defensive ditch dug around the perimeter. At Carrowroe, that fosse was still identifiable when a report was filed in 1975, but it has since disappeared entirely from the visible landscape, absorbed or disturbed by the ordinary pressures of farming over the intervening decades. A modern field wall runs along the north-western to northern arc of the bank's outer base, and a farm building now occupies part of that same edge. The original entrance into the enclosure has been lost, and a quarry hole sits just inside a more recent opening cut into the eastern side, a small but telling sign of how thoroughly the working land has reworked what was once a defined and purposeful boundary.