Craigellachie Bridge is a cast iron arch bridge located in Speyside, near to the village of Aberlour. Designed by Thomas Telford FRS, it was built from 1812-1814; the original plan was for a lower bridge, but Telford took advice from local people and raised it by several feet. It was the only bridge on the Spey to survive the great floods of 1829.

The bridge has a single span of approximately 46 m. (151 ft) and was revolutionary for its time, in that it used an extremely slender arch which was not possible using traditional masonry construction. The ironwork was cast at the Plas Kynaston iron foundry at Cefn Mawr, near Ruabon in Denbighshire by William Hazledine, who cast a number of Telford bridges. The ironwork was transported from the foundry through the Ellesmere Canal and Pontcysyllte Aqueduct then by sea to Speymouth, where it was loaded onto wagons and taken to the site. Testing in the 1960s revealed that the cast-iron had an unusually high tensile strength. This was likely specified by Telford because, unlike traditional masonry arch bridges, some sections of the arch are not in compression under loading.

At each end of the structure there are two 15 metres (49 ft) high masonry mock-medieval towers, featuring arrow slits and miniature crenellated battlements.

The bridge was in regular use until 1963, when it was closed for a major refurbishment. The side railings and spandrel members were replaced with new ironwork fabricated to match the originals. A 14 ton restriction was placed on the bridge at this point. This, along with the fact that the road to the north of the bridge takes a sharp right-angled turn to avoid a rock face, made it unsuitable for modern vehicles. Despite this it carried foot and vehicle traffic across the River Spey until 1972, when its function was replaced by a reinforced concrete bridge built by Sir William Arrol & Co. which opened in 1970 and carries the A 941 road today. Telford's bridge remains in good condition, and is still open to pedestrians and cyclists.

The bridge has been given Category A listed status by Historic Scotland and has been designated a civil engineering landmark by the Institution of Civil Engineers.

The black plaque (see image 4) reads:

Craigellachie Bridge, designed and built by Thomas Telford, 1814

Restored to its original design by the County Councils of Banff, Moray & Nairn, 1964

The foreground plaque reads:

International Historic Civil Engineering Landmark, Craigellachie Bridge.

Erected 1812-14 span 150ft deck strengthened 1902

Reconstructed above ribs with significant preservation 1963-4

Engineers: Thomas Telford; W.A. Fairhurst & Ptnrs (1963-4)

Ironfounder and erector. William Hazledine, Ruabon, Wales

Contractors: John Simpson & John Cargill;

William Tawse Ltd & Sir William Arrol Ltd (1963-4)

Earliest survivor of Telford's landmark prefabricated lozenge-lattice cast-iron arch bridge type developed for deep river sites impracticable for stone bridges - In nationwide use by 1830. Cost £8,200. Ironwork brought from Speymouth in wagons

Presented to the Moray council in the 250th anniversary year of Telford's birth by The Institute of Civil Engineers and The American Society of Civil Engineers, 4 July 2007.