Penrhyn Bridge, including parapet walls on the approach road to Penrhyn Castle Port

Coursed rubble. Single segmental arch with voussoirs, keystone and arch ring; iron plaque over the raised lettering. The parapet appears to have been rebuilt and has ironwork balustrade. Advanced piers at either end with tall concave recess and swept out bases; the roadway is carried to either side by revetment walls slightly swept out.

The parapets continue on the E bank towards the entrance to Penrhyn Castle with regularly spaced low piers; on the N side the parapet sweeps up over a garden door and curved back to end at a large square pier adjoining the Customs House; on the S side the parapet continues as far as the gate into the adjoining field. To W end the wall ramps down on N side and sweeps up to end on S side joining boundary wall rising to Llandegai Road. Old photographs show that the bridge had iron gates at the W end.

At the E end blow the roadway are 2 segmental arched openings with boarded doors; one to N side partly bricked up. These were originally the arches through which the LNWR Port Siding and Penrhyn Quarry Railway passed - the tracks led directly to the harbour.