Long tradition attributes the design of Llanrwst Bridge to Inigo Jones in 1636, but the connection is probably because Richard Wynn of Gwydir acted as Treasurer to the Queen and would have paid Jones and his master mason Nicholas Stone, from whom Wynn commissioned a plaque for Llanrwst church in 1634. It is possible that the design of the bridge is based on Palladio's not-dissimilar design for a three-arch bridge of 60 ft (18 metres) main span and 48 ft (15 metres) outer spans.

The Llanrwst bridge has 60 ft and 40 ft (12 metres) spans.The west arch is known to have been rebuilt in 1675, and again in 1703. Built of coursed local gritstone and slate rubble, the bridge is a steeply ramped road bridge of three segmental arches. Cutwaters to each side continue upwards to form refuges in the parapet. The parapet has heavy chamfered coping stones with iron cramps. There are flared approach walls.

Above the apex of the central arch, the south parapet has a stone relief of the Stuart Arms (plus the initials 'CR') set in a frame with superimposed fluted columns supporting floral entablature and ogee cresting; below the arms is the date '1636'. A sundial above was installed for the tercentenary of the bridge. The north parapet has, in the same position, the Prince of Wales feathers springing from a crown; flanked by the initials 'CP'; the inner parapet has carriage stones to protect the masonry. A stone on the inner south parapet above the rebuilt west arch has the initials 'TR'.

Source: Cadw listed buildings database.
Source: Haslam, Orbach and Voelcker (2009), The Buildings of Wales: Gwynedd. Pevsner Architectural Guide, page 381.

RCAHMW, October 2009