Parc le Breos Cwm in the Gower 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 6,000 years ago, during the early Neolithic. It is about seven miles west south–west of Swansea, in what is now known as Coed y Parc Cwm on the Gower Peninsula.

The shape of the tomb is trapezoidal – with the upper part of the cromlech and its earth covering now removed – surrounded a low dry-stone wall. A bell-shaped, south-facing forecourt, formed by the wall, leads to a central passageway lined with limestone slabs set on end. Human remains had been placed in the two pairs of stone chambers that lead from the passageway. Corpses may have been placed in nearby caves until they decomposed, when the bones were moved to the tomb.

The cromlech was discovered in 1869 by workmen digging for road stone. An excavation later that year revealed human bones (now known to have belonged to at least 40 people), animal remains, and Neolithic pottery. Samples from the site show the tomb to have been in use for between 300 and 800 years. North-West European lifestyles changed around 6000 years ago, from the nomadic lives of the hunter-gatherer, to a settled life of agricultural farming.

The chambered tomb lies in a former medieval deer park, established in the 1220s by the Marcher Lord of Gower as Parc le Breos – an enclosed area of about 2,000 acres, now mainly farmland. The monument is on the floor of a dry narrow limestone gorge containing about 500 acres of woodland.