This historic road follows the upper Elan Valley from the east, crossing into the Ystwyth at Blaen y Cwm. It is shown on Ogilby's road map of 1675 and may be based on an earlier medieval route. During the 18th century it was improved as a turnpike road, around 1790. More recently, during the 20th century, further improvements were made , with some straightening and widening undertaken, and the whole road being tarmaced. The modern roadway is well maintained. Some sections of the earlier turnpike or county road can still be seen running parallel to the modern road. J.J. Hall, Trysor, 29 October 2009