This shows up as a henge on www.Archaeology.ie , dont know much else about it except that. On inspecting it looks a lot more like a normal ring-fort. I couldnt see any sign of an internal ditch but in fairness it was very overgrown. Might be worth a look in winter when the grass has died back a bit. It is located about 4 kms north west of Listowel. You can easily park next to a graveyard which is right beside it.