Parc Cwm long cairn (Welsh: carn hir Parc Cwm), also known as Parc le Breos burial chamber (siambr gladdu Parc le Breos), is a partly restored Neolithic chambered tomb, identified in 1937 as a Severn-Cotswold type of chambered long barrow. The cromlech, a megalithic burial chamber, was built around 5850 years before present (BP), during the early Neolithic.