Viaduc de la Roizonne, Railway bridge in La Mure, France.

The Viaduc de la Roizonne is a railway bridge that extends 260 meters across the landscape while standing 110 meters high above the ground. Its design uses a series of arches, with a large semicircular arch forming the main span and smaller arches supporting the sections above.

Construction began in 1913 under engineer Paul Séjourné, with the Grenoble firm Pascal carrying out the work. Delayed by the First World War, the viaduct was finished in 1929; the La Mure–Valbonnais line opened in 1926, while the main line to Corps waited for the Viaduc de la Bonne in 1932. The line was decommissioned in 1952 and the viaduct was converted to road use on the RD 26.

The viaduct carried the metre-gauge, electrically powered line from La Mure towards Corps; the section to Valbonnais opened in 1926, before the viaduct was finished. The line closed in 1952, and the deck now carries the RD 26 road between La Mure and Valbonnais. Near the crossing stood the old bridge by the village of Roizon, below the castle of Rattier.

The viaduct stands about 2 kilometers east of La Mure and can be viewed from a nearby road that passes below or near the structure. The best time to visit is during clear weather, when the bridge's form stands out clearly against the sky.

The main arch was built on timber scaffolding launched from both slopes, with a suspended cradle carrying materials to the centre. Its deck was widened and consolidated in spring 2009 by the Isère general council, a project costing 2.2 million euros.