One is a ringfort, a familiar enough type of enclosed farmstead used throughout early medieval Ireland. The other, lying just to its west, is considerably harder to make out: an oval earthwork, running about fifty metres north to south and forty metres east to west, whose defining bank has been so thoroughly swallowed by vegetation that the outline is more suggested than seen.

What survives is slight but legible if you know what to look for. The enclosure is roughly oval in plan, and at its north-western edge there is a shallow depression that may mark the course of a fosse, the external ditch that would originally have reinforced the bank. Fosses were a standard feature of enclosed sites across prehistoric and early medieval Ireland, dug to provide both the raw material for the bank and an additional physical barrier. Whether the Castlegar enclosure is contemporary with its ringfort neighbour, subordinate to it, or of an entirely different period, the available evidence does not say. The proximity of the two sites is suggestive, though what exactly it suggests remains open.