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Two Round Cairns at Onllwyn is a prehistoric round cairn located in Wales. The monument comprises two distinct cairn structures positioned on bedrock of Dinantian limestone, sandstone and argillaceous rocks. Round cairns of this type were constructed during the Bronze Age as funerary monuments, typically serving as burial places for high-status individuals. The geological foundation at Onllwyn would have provided stone suitable for cairn construction, with the local limestone and sandstone naturally available for gathering and stacking.
The monument is situated in an area of south Wales where similar Bronze Age burial monuments cluster across the upland terrain. The two-cairn arrangement suggests a sequence of use or separate but closely associated burials, a pattern found at other contemporary sites. Stone of the required size and weight would have been readily available from the surrounding Mississippian bedrock.
The site is protected as a scheduled monument by Cadw under the reference GM529. This statutory protection recognises its archaeological significance as evidence of Bronze Age burial practice and social organisation in prehistoric Wales. The monument remains a tangible record of the people who invested substantial labour in its construction.
Two Round Cairns at Onllwyn is a scheduled monument protected by Cadw under reference GM529. View the official record →
Two Round Cairns at Onllwyn is a prehistoric round cairn located in Wales. It is designated a Scheduled Ancient Monument by Cadw under reference GM529.
Two Round Cairns at Onllwyn dates from the prehistoric period, and is classified as a round cairn. It is one of over 32,000 scheduled monuments protected across the UK.
Two Round Cairns at Onllwyn 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 GM529.
Several scheduled monuments lie within 10 km, including Iron Tram Bridge, Robertstown (6 km), Tramroad East of Robert's Town Bridge, Aberdare (6 km), Gadlys Ironworks (Remains of Blast Furnace) (6.6 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Two Round Cairns at Onllwyn'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.
Two Round Cairns at Onllwyn stands on Dinantian Rocks (Undifferentiated), bedrock that formed in the Mississippian. The rock here is limestone with subordinate sandstone and argillaceous rocks.