If your solicitor has an online Property Registration Authority Account they can look it up on line for you. You'd need to know roughly where it is, the townland or be able to describe the place, address, and identify it on the OS map.
I often have clients call in with this question and look it up for them there and then. If it is registered ( and over 90% of the land mass of ireland is) they can search for the last registered owner then after identifying it on the map.