The route of the new trunk road is a route at Bryn Sadwrn in the County of Powys as follows:—
A route about 1,275 metres in length, starting at a point on the trunk road about 150 metres north of its junction with the Classified Road C212 and C357 and running in a northerly direction to a point on the trunk road about 20 metres south of its junction with the unclassified road to Neuadd Farm.