Splügen (Romansh: Spleia, Italian: Spluga) is a former municipality of the district of Hinterrhein in the canton of Graubünden in Switzerland.. On 1 January 2006 Splügen incorporated its neighbouring municipality of Medels im Rheinwald. On 1 January 2019 the former municipalities of Hinterrhein, Nufenen and Splügen merged to form the new municipality of Rheinwald.