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Nant-Gronw Round Barrows is a prehistoric round barrow located in Wales and protected as a scheduled monument by Cadw under reference CM109. The site sits upon Ashgill Rocks, an undifferentiated sequence of mudstone, siltstone and sandstone deposited during the Ashgill period of the Ordovician era. This solid bedrock foundation would have presented considerable challenges to Bronze Age communities constructing burial mounds across the landscape, requiring significant labour to excavate and move earth and stone for the barrow's construction.
Round barrows of this type typically served as burial monuments for individuals of social standing within their communities, constructed over several centuries during the Bronze Age. The Ashgill geology underlying Nant-Gronw would have influenced both the character of the surrounding terrain and the construction methods employed by monument builders, who necessarily worked with locally available stone and soil.
The monument's continued survival and formal protection reflects its archaeological significance as evidence of early burial practices and social organisation in prehistoric Wales. Its preservation enables ongoing study of Bronze Age settlement patterns, funerary customs and the relationship between communities and their landscape during this formative period of Welsh prehistory.
Nant-Gronw Round Barrows is a scheduled monument protected by Cadw under reference CM109. View the official record →
Nant-Gronw Round Barrows is a prehistoric round barrow located in Wales and protected as a scheduled monument by Cadw under reference CM109.
Nant-Gronw Round Barrows dates from the prehistoric period, and is classified as a round barrow. It is one of over 32,000 scheduled monuments protected across the UK.
Nant-Gronw Round Barrows is a Scheduled Ancient Monument, legally protected by Cadw — the body responsible for designating and safeguarding heritage sites in Wales. The official designation reference is CM109.
Several scheduled monuments lie within 10 km, including Cynwyl Elfed Anti-invasion Defences (5.8 km), Defended Enclosure 300m W of Pen y Gar (6 km), Bwlch-Bychan Round Barrow (6.7 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Nant-Gronw Round Barrows's history, each drawn from the record and mapped to the exact spot:
Every location is different. Not every section appears for every place, only what the historical record actually holds turns up in a report.
Nant-Gronw Round Barrows stands on Ashgill Rocks (Undifferentiated), bedrock that formed in the Ashgill. The rock here is mudstone, siltstone and sandstone.