Pont Briwet refers to the road and railway bridges that cross the River Dwyryd, near Penrhyndeudraeth, Gwynedd in North Wales.

The new Pont Briwet crosses the Dwyryd on the same alignment as the original structure but it is both stronger and wider to accommodate larger vehicles and traffic volume.

It also accommodates a combined cycle path and pedestrian walkway, as well as carrying multiple utilities, such as water and electricity, across its structure.

[2] During 1861 and 1862, the Aberystwith and Welsh Coast Railway company was authorised by an Act of Parliament to construct a coastal line along Cardigan Bay between the city of Aberystwyth and Porthdinllaen on the Lleyn Peninsula.

[3] During February 1866, the construction of the bridge was dealt a major setback when the contractor responsible for building it, Thomas Savin, was declared bankrupt.

[2] The road over the bridge acted to remove an otherwise-necessary 13 kilometre (8 mile) detour via Maentwrog, a major boon to local residents.

[2] The original Pont Briwet was a timber pile viaduct, which were a commonplace feature of coastal railways during this era, being relatively cheap and flexible structures in comparison to the common alternatives.

The bridge was furnished with substantial battered abutments, composed of rough blocks of slate that were in excess of 40 metres in terms of length.

[3] Reportedly, the bridge and line benefited heavily from the freight traffic generated after the establishment of Cooke's explosives factory near Penrhyndeudraeth during 1872.

The closure necessitated an 8-mile diversion via Maentwrog for road users and rail services were terminated at Harlech, closing the 22 miles (35 km) line to Pwllheli via Porthmadog.

The design of the replacement bridge features the extensive use of the innovative precasting technique which accelerated the construction activities and minimised the disruption to surrounding watercourse.

[19] However, work continued into the following year on the accompanying roadway; progress on its construction had been delayed by difficulty in the relocation of electricity cables and a water main that previously crossed the old bridge.