Alter Rhein

This article is about describes the Old Rhine that flows into Lake Constance. For other uses, see Old Rhine.

The Alter Rhein near Höchst

The Alter Rhein at Hohenems, on the border with Diepoldsau

The Alter Rhein (German for Old Rhine) is the old river bed of the Alpine Rhine in St. Gallen and Vorarlberg in the Rhine Valley, which was cut off when the Rhine was straightened during the 20th century. These cut-off arms have become valuable recreational areas and a nature reserve.

In 1900, the short-cut at Fussach was completed. The old river course, from Höchst and St. Margrethen to the village of Altenrhein in Tahl on the shore of Lake Constance forms the border between Austria and Switzerland. In 1906, the [Rheintaler Binnenkanal] Error: {{Lang}}: text has italic markup (help) ("Rhine Valley Inland Canal") was dug, connecting Sennwald to St. Margrethen. In 1923, another short-cut was completed at Diepoldsau, creating another dead branch, also named Alter Rhein.

The area between the Old and New Rhine forms the nature reserve Rhine Delta (not to be confused with the Rhine Delta in the Netherlands).

View from the Hohe Kugel on the old and new Rhine at Diepoldsau