The Tarn (French pronunciation: [taʁn] ; Occitan: Tarn, Latin: Tarnis, possibly meaning 'rapid' or 'walled in') is a 380.2-kilometre (236.2 mi) long river in the administrative region of Occitania in southern France. It is a right tributary of the Garonne.
The Tarn runs in a roughly westerly direction, from its source at an elevation of 1,550 m (5,090 ft) on Mont Lozère in the Cévennes mountains (part of the Massif Central), through the deep gorges and canyons of the Gorges du Tarn that cuts through the Causse du Larzac, to Moissac in Tarn-et-Garonne, where it joins the Garonne, 4 km (2.5 mi) downstream from the centre of town.