The Rabiusa (Romansh: Rabiosa, i.e. "Raging", in the local German dialect Rii, i.e. "Rhine") is a 32 km long tributary of the Rhine. The river originates in the district Hinterrhein in the canton of Graubünden, in the mountains surrounding the Bärenhorn (2929 m), where the old bridle path from Safien to Splügen crosses the Safierberg Pass (2486 m). It then flows through the wooded Safien valley and into the rough Versam Gorge, where it is spanned by the Versam Gorge Bridge.