Viaduc de Gien, Railway bridge in Gien, France.

The Viaduc de Gien is a railway bridge of 1,832.20 metres crossing the Loire between Gien and Poilly-lez-Gien. It consists of three structures: a masonry viaduct of 1,198.20 metres on the left bank, a 361-metre metal truss bridge over the river, and a 273-metre masonry viaduct on the right bank. The photograph shows light grey and tan masonry blocks, a flat deck with a low metal railing on short posts, and arches on thick rectangular piers, weathered with dark stains at the base.

Built between 1888 and 1893, this structure ranked among the three longest bridges in the world at that time. It opened the railway connection between Gien and Poilly-lez-Gien.

The viaduct's name comes from Gien, the town on the right bank where the line reaches the station on its plateau. The crossing was studied from 1878, and the ministerial decision of 17 April 1882 approved a design with 96 arches of 11 metres on the left-bank valley. Freight trains still run only between Gien and Poilly-lez-Gien.

The masonry section on the left bank runs through the flat Loire valley between Poilly-lez-Gien and the river, where the arches can be followed from the roads below. The metal truss over the water is best seen from the banks near the old bridge of Gien, upstream. Only the Gien–Poilly-lez-Gien section still carries freight, so no passenger service runs here.

The structure divides into three separate sections that showcase different construction methods. This arrangement makes it possible to clearly observe how stone masonry techniques meet modern steel engineering.