A single-arched bridge crossing the Afon Cegin to access the Port Lodge and drive to Penrhyn Castle. The arch ring and abutments, the latter with vacant semicircular-headed niches, are of carefully dressed Penmon limestone, and the date of building, 1820, is recorded on a cast iron plate on the north side, together with the initials of George Hay Dawkins Pennant, who inherited the Penrhyn Estate from Richard, 1st Baron Penrhyn. The roadway appears to have been raised by the addition of three courses of rough ashlar, and the bridge parapets are completed by wrought iron railings.
To the east the almost level road passes over two more arches which crossed the narrow gauge Penrhyn Railway to the slate quarries and the L&NWR standard gauge branch of 1852 to Porth Penrhyn.
W J Crompton, RCAHMW, 23 October 2009.