On 21st July 1845, a Parliamentary Act was passed authorising George Hudson's York & North Midland Railway to construct a 18½-mile line connecting Church Fenton with Harrogate. The route was staked out two months later and opened as far as Spofforth on 10th August 1847. The remainder of the line into Harrogate involved major engineering works including the 31-arch Crimple (Valley) Viaduct and two tunnels totalling 1,240 yards. It was completed on 20th July 1848. The whole venture cost the company £607,000. The route was unfavourably graded, with one 5½-mile section rising continuously at 1:101 or steeper.
Three miles south-east of Wetherby, the line crossed the River Wharfe on a 162-yard viaduct, constructed in three distinct parts: five-arch masonry structures on either bank connected by two fabricated steel plate girder spans across the water. The latter are later replacements.
Forming the approach viaducts are limestone blocks with rock-faced voussoirs and brick arch barrels. Ashlar is used for the cutwaters and string course. The parapets have mostly been lost except on the west side of the northern structure.
On each bank are abutments with domed cutwaters. Their river-facing sides feature seats which braced the four cast-iron arches that originally formed each of the two river spans. This arrangement is repeated on the pier standing in the water. The replacement steel girders were narrower than their predecessors so walkways were built out on both sides, supported by triangular brackets to which handrails were also attached.
The section of line to the south of Wetherby - crossing the viaduct - survived until 4th April 1966. Today it is Grade II listed but its condition is generally poor, with cracks apparent in the piers, spandrels and arches. Remedial work has been carried out, as evidenced by the many pattress plates and tie bars installed.
Plans were lodged in 2005 to open a footpath across the structure as part of the redevelopment of a former paper mill for office space and housing. Around £1 million would have been invested in repair work to the viaduct. Planning consent for the scheme was granted in 2011 but this has not yet been exercised.