Nant Carn Aqueduct was built in the mid 1790s by Thomas Dadford junior, to carry the Crumlin arm of Monmouthshire Canal (Company). The bridge carrying the Western Valley Road over the Nant Carn brook was built alongside and parallel to the aqueduct. Both were destroyed following the Cwmcarn Dam disaster of 1875 and subsequently rebuilt. The aqueduct now marks the northernmost surviving limit of Monmouthshire Canal (Company). It has a small single span, segmental arched passageway, and squared rubble with ashlar quoins and voussoirs.

Claire Parry, RCAHMW, 28 June 2011.

Source: A Guide to the Industrial Archaeology of South East Wales, AIA, 2003