The Rhine Valley (German: ) is a glacial alpine valley, formed by the part of the Alpine Rhine (German: ) between the confluence of the Anterior Rhine and Posterior Rhine at Reichenau and the Alpine Rhine's mouth at Lake Constance. From Reichenau, the Alpine Rhine flows east, passing Chur and turning north, forms the border between the Canton of St. Gallen of Switzerland on the left, west side and first Liechtenstein and then Vorarlberg, Austria on the right, east side. The Swiss-Austrian border follows the historical bed of the Rhine, but today the river follows an artificial canal within Austria for the final .