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Cairn Lwyd is a prehistoric round cairn situated in Wales and protected as an ancient monument by Cadw (reference GM238). The monument lies upon bedrock of the South Wales Upper Coal Measures Formation, a geological sequence laid down during the Westphalian age. This underlying strata comprises alternating bands of mudstone, siltstone and sandstone interspersed with coal seams, ironstone and ferricrete, the iron-rich hardened layers characteristic of this Carboniferous coalfield geology.
As a round cairn, the monument represents a burial or ceremonial structure built during prehistoric times, its form typical of ritual monuments constructed across the upland zones of Wales during the Bronze Age and earlier periods. The use of locally available stone, quarried or gathered from the landscape above the Coal Measures bedrock, would have been fundamental to the cairn's construction. The substantial geology beneath the site—particularly the harder ferricrete bands—would have influenced both the procurement of suitable building materials and the choice of this location.
The monument's survival and protection under Cadw reflects the archaeological importance of such cairn sites in understanding prehistoric settlement, burial practice and land use across the Welsh uplands. Despite centuries of land use and weathering, Cairn Lwyd remains a tangible reminder of the monumental ambitions of prehistoric communities who worked the difficult terrain of the South Wales coalfields.
Cairn Lwyd is a scheduled monument protected by Cadw under reference GM238. View the official record →
Cairn Lwyd is a prehistoric round cairn situated in Wales and protected as an ancient monument by Cadw (reference GM238).
Cairn Lwyd 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.
Cairn Lwyd 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 GM238.
Several scheduled monuments lie within 10 km, including Remains of Tondu Ironworks (6.3 km), Three Pillow Mounds on Cefn Hirgoed (7.4 km), Derwen Moated Site (7.7 km).
This page is just one thread. A full Aubrey report pulls together 13 strands of Cairn Lwyd'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.
Cairn Lwyd stands on South Wales Upper Coal Measures Formation, bedrock that formed in the Westphalian. The rock here is mudstone, siltstone, sandstone, coal, ironstone and ferricrete.