CN338

The Holyhead Road: the Ogwen Pass  

22/11/2004  

Designated  

Gwynedd  

Llanllechid  

264776  

360785  

Transport  

Road  

Post Medieval/Modern  

The following provides a general description of the Scheduled Monument. The monument comprises the long stretch of revetment walling that accommodates Thomas Telford's Holyhead Road on the E side of Nant Ffrancon, as it rises to reach the Ogwen Pass; and the clearly visible earlier turnpike road beneath. Telford described the new road as follows: "This road established through a rugged and mountainous district, partly along the slope of rocky precipices, and across inlets of the sea… was indeed an arduous undertaking, which occupied fifteen years of incessant exertion". Telford was commissioned by Parliament in 1811 to report on the important route between Holyhead and London. The existing roads were themselves relatively recent improvements on earlier tracks, put in place by turnpike trusts over the previous thirty years. However, the investment was not always great and the roads were characterised by steep gradients, sharp bends and badly drained or potholed surfaces. Work on the Welsh section of the Holyhead Road commenced in 1815 and, upon the completion of the Menai Bridge in 1826, was greeted with acclaim as the finest road in Europe. The alignment and shallow gradient of Telford's road can easily be appreciated, as can the scale of the cutting and blasting required to construct it; and can be compared to the winding undulating turnpike road beneath it. The revetment for the turnpike is of rough drystone, which contrasts with the fine revetment of the Telford road up to 6m higher. The route of the earlier turnpike has a substantial rock cutting, revetment and a fragmentary arch preserved beneath Telford's bridge. The monument is of national importance as a well preserved and exciting section of a road with international significance, with evidence of the engineering work which preceded it. The importance of the monument is further enhanced by the survival of detailed historical documentation. The scheduled area comprises the remains described and an area around them within which related evidence may be expected to survive. It is irregular on plan and measures 740m from NE to SW by up to 30m transversely. The scheduled area on the NE extends to the inside of the parapet of the upper revetment wall (that of Telford's road), while on the SW it extends to the base of the lower revetment wall (that of the turnpike road). The scheduled area is a straight line on the NW, extending from the base of the lower revetment wall to the inside of the parapet of the upper retaining wall. The scheduled area on the SE extends to the top of the face of the SW side of the cutting through which the earlier turnpike was lain; and extends to include the base of the lower revetment wall to the S of the rocky knoll and includes the earlier arch of bridge in its entirety.