Rueun is a former municipality in the district of Surselva in the canton of Graubünden in Switzerland . On 1 January 2014 the former municipalities of Rueun, Castrisch , Ilanz, Ladir , Luven , Pitasch , Riein , Ruschein , Schnaus , Sevgein , Duvin , Pigniu and Siat merged into the new municipality of Ilanz/Glion .

Rueun is first mentioned in 765 as Ruane. Until 1943 Rueun was known as Ruis.

The blazon of the municipal coat of arms is Gules St. Andrew issuant holding a wooden saltire cross. The motif of St.