A product of the Coleford, Monmouth, Usk and Pontypool Railway, the 256-yard tunnel at Usk was cut through the hill immediately to the east of the town’s station. It became part of the network on 12th October 1857 and waved goodbye to its last train on 30th May 1955 although a rail tour passed through it on the day of its centenary.
Both portals are masonry with the eastern one supported by substantial buttresses. Whilst the roof is bricked-lined, the walls - with their occasional refuges - are a variety of brick and stone. The profile of the tunnel changes on numerous occasions and a considerable kink occurs in the centre due to a pair of skewed, offset strengthening rings.
Despite being unlit, the tunnel is now officially part of a footpath and the floor has been raised with infill for this purpose to keep the feet of users dry. This has resulted in a water channel being formed at the foot of the south wall.