Poulnabrone dolmen (Irish: Poll na Brón, lit. 'Hole of the Quernstone') is a large dolmen (or cromlech, a type of single-chamber portal tomb) located in the Burren, County Clare, Ireland. Situated on one of the region's most desolate and highest points, it comprises three standing portal stones supporting a heavy horizontal capstone and dates to the early Neolithic period, with estimates from 3800 and 3200 BC. Although not the largest, it is the best known of the approximately 172 dolmens in Ireland.
It was constructed on a unique karst landscape formed from limestone laid down around 350 million years ago. The dolmen was built by Neolithic farmers, who chose the location either for ritual, as a territorial marker, or as a collective burial site. What remains today is only the "stone skeleton" of the original monument; originally, it would have been covered with soil, and its flagstone capped by a cairn.