Tiefencastel (Romansh: Casti) is a former municipality in the district of Albula in the canton of Graubünden in Switzerland. On 1 January 2015 the former municipalities of Alvaschein, Mon, Stierva, Tiefencastel, Alvaneu, Brienz/Brinzauls and Surava merged to form the new municipality of Albula/Alvra.