The Alpine Rhine Valley is a glacial alpine valley, formed by the part of the Alpine Rhine between the confluence of the Anterior Rhine and Posterior Rhine at Reichenau and the Alpine Rhine's mouth at Lake Constance. It covers three countries and the full length of the Apine Rhine is 93.5 km.
From Reichenau, the Alpine Rhine flows east, passing Chur and turning north, before it turns north-east at Landquart, and then roughly north, east of Sargans. From here, the Alpine Rhine forms the border between the canton of St. Gallen of Switzerland on the left, west side, and the Principality of Liechtenstein on the east side. About 28 kilometres further down, the Rhine then meets the Austrian federal state Vorarlberg and finally flows into Lake Constance, south of Lindau , which is no longer part of the Rhine Valley. The Swiss-Austrian border follows the historical bed of the Rhine, but today the river follows an artificial canal within Austria for the final 5 kilometres .