A487 road

The section of road in the Dulas valley between the River Dyfi near Machynlleth and Corris was built in the 1840s at the instigation of the local slate quarry owners to replace the old turnpike road on the opposite side of the valley. It may have utilised part of the formation of the Roman Sarn Helen. From 1859, the narrow-gauge Corris Railway followed the same route. The site of Dolgellau railway station, along with approximately 1.5 mi of trackbed of the Ruabon–Barmouth line, was used to construct the Dolgellau bypass in the late 1970s. In 1989–90, Cardigan was bypassed south of the town with a new Priory Bridge over the River Teifi and a short 3-lane section between the bridge and the…