Hinterrhein District is a former administrative district in the canton of Graubünden, Switzerland. It had an area of 617.67 km2 and had a population of 13,179 in 2015. Much of the district became part of the Viamala Region on 1 January 2017 as part of a reorganization of the Canton. Hinterrhein District consisted of five Kreise (sub-districts) and twenty-four municipalities. This number decreased from thirty-two when the municipalities of Portein, Präz, Sarn, and Tartar merged on 1 January 2010 into Cazis. It decreased further in 2015 when Almens, Paspels, Pratval, Rodels and Tomils merged to form the new municipality of Domleschg.

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