It stands roughly three metres high with an exterior diameter of four metres, built in drystone fashion from rough limestone blocks and spalls, and at its south-south-west face two straight lines in the walling suggest a doorway, about 0.95 metres wide, that was blocked up at some point. Whether it was a tower, a tomb, or a navigational marker remains genuinely open.

The structure sits on elevated ground overlooking Inis Meáin to the south-east, which places it in a commanding position above the sound that bears the name of St Gregory. That association is not incidental: the ruin is reputedly the grave of St Gregory himself, a tradition recorded by the antiquarian T. J. Westropp in 1895. The round tower identification, which would place it in the tradition of the tall, freestanding stone towers built beside early Irish monasteries, was considered and rejected by Lennox Barrow in 1979. Barrow proposed instead that the structure served as a seamark, a fixed point of reference for boats navigating the waters between the Aran Islands. That reading would make it less a monument of devotion and more a piece of practical geography, though the two purposes need not have been mutually exclusive in a landscape so thoroughly shaped by early Christian use. Its date remains uncertain.