Naut Aran (Occitan pronunciation: [ˈnawt aˈɾan]) is a municipality in the comarca of the Val d'Aran in Catalonia, Spain. It is the second largest municipality in Catalonia in terms of surface area (225.8 km², behind Tremp), and was created in 1967 by the merger of the municipalities of Arties, Salardú, Gessa, Tredòs and Bagergue: the former municipalities retain some privileges as "decentralised municipal entities" (entitats municipals descentralitzades, EMD). The name literally means "Upper Valley" in Aranese, and both the Garonne (Garona) and the Noguera Pallaresa have their sources on the territory of the municipality. The town hall is in Salardú. The municipality is linked to Vielha by the C-28 road, which continues to Alt Àneu over the Port de la Bonaigua (2072 m). This road, the higher stretches of which are impassable in winter, was the only route between the Aran Valley and the rest of Spain before the opening of the Vielha tunnel in 1948.