Garndiffaith Viaduct

Garndiffaith Viaduct crosses the Afon Lwyd river valley using nine arched spans constructed from squared stone and brick. The bridge now carries pedestrians and cyclists across the valley as part of a modern recreational route.

The viaduct was built between 1876 and 1877 as part of a railway expansion connecting different networks across Wales. It played an important role in transporting goods and people during the height of industrial railway development in the region.

The structure displays hallmarks of Victorian engineering craft and stands as a reminder of the industrial transformation that reshaped the Welsh valleys. Visitors can still observe the quality of the stonework and brick arches that characterize this era.

The structure is accessible today via the National Cycle Network Route 46, which offers a safe path across the valley for pedestrians and cyclists. Visit during dry weather when possible, as the surface can become slippery when wet.

The structure has an unusual asymmetrical shape because the deck width changes significantly from one span to another. This distinctive form resulted from the original railway engineering requirements and makes the bridge an unexpected study in functional geometry.

GPS coordinates: 51.73270,-3.06870

Latest update: December 14, 2025 14:24