The Lignon (French: le Lignon) is a 20.7 km (12.9 mi) long river in the Ardèche département, southern France. Its source is at La Souche, in the Parc naturel régional des Monts d'Ardèche. It flows generally east-northeast. It is a right tributary of the Ardèche into which it flows between Meyras and Pont-de-Labeaume.
