Mauzac-et-Grand-Castang (French pronunciation: [mozak e ɡʁɑ̃ kastɑ̃]; Occitan: Mausac e Grand Castanh) is a commune in the Dordogne department in Nouvelle-Aquitaine in southwestern France.

The village has been occupied from prehistoric times, as is evidenced by numerous traces (fragments of axes, scrapers...).

Its past is closely linked with the Dordogne River, which became an important commercial and cultural route in the 18th and 19th centuries.

Only a few vestiges of the built quay remain, just some paving stones cut in the old-fashioned way, identical to those still seen in Bordeaux.

Constructions of the Canal de Lalinde to facilitate navigation for the scows, of the hydroelectric dam, and the arrival of the railway in the 19th century, changed the life of the village considerably.