The Saar is a minor tributary of the Alpine Rhine in the Swiss canton of St. Gallen. It rises in Mittelsäss, Bad Ragaz municipality, at 2,087 m elevation. Flowing generally north, it passes the Saarfall waterfall, dropping from 560 m to 500 m, reaching the plain of the Rhine Valley. From here, it is strongly canalised, flowing through the territories of the Vilters-Wangs, Mels and Sargans municipalities before joining the Rhine downstream of Trübbach at 480 m.