Welland Viaduct, also known as Harringworth Viaduct and Seaton Viaduct, is a railway viaduct which crosses the valley of the River Welland between Harringworth in Northamptonshire and Seaton in Rutland, England. It is 1,275 yards (1.166 km) long and has 82 arches, each of which has a 40 feet (12 m) span. The viaduct was built by Lucas and Aird and completed in 1878. It is the longest masonry viaduct across a valley in Britain and a Grade II listed building. The first brick was laid in March 1876 and the last arch was finished in July 1878. Welland Viaduct from Seaton in 2009