| Töss | |
| Image Alt: | The river Töss in Rikon im Tösstal |
| Subdivision Type1: | Country |
| Subdivision Name1: | Switzerland |
| Subdivision Type2: | Canton |
| Subdivision Name2: | Zürich |
| Source1: | Confluence of the Vordertöss and Hindertöss |
| Source1 Location: | Tössscheidi, Wald ZH and Fischenthal, ZH, Switzerland |
| Source1 Coordinates: | 47.3123°N 8.9604°W |
| Mouth Location: | Tössegg, Freienstein-Teufen, ZH, Buchberg, SH, Eglisau, ZH, Switzerland |
| Mouth Coordinates: | 47.5521°N 8.5541°W |
| Length: | 56km (35miles) |
| Source1 Elevation: | 796m (2,612feet) |
| Mouth Elevation: | 344m (1,129feet) |
| Basin Size: | 441.43 km2 |
| Tributaries Left: | Vordertöss, Mülibach, Cholerbach, Fischbach, Kempt, Mülibach, Wildbach |
| Tributaries Right: | Hintertöss, Brüttentalbach, Fuchslochbach, Tobelbach, Lochbach, Steinenbach, Ägetswilerbach, Sackbach, Chatzenbach, Eulach, Näfbach, Tobelbach, Tüfenbach |
The Töss is a river in the Swiss canton of Zürich and a tributary of the High Rhine (German: Hochrhein). It starts at Tössscheidi, the confluence of the Vordertöss and Hindertöss (whose sources are in the canton of St. Gallen), passes through Winterthur's Töss and Wülflingen districts and ends at German: Tössegg near Freienstein-Teufen. Two of its main tributaries are the Kempt and Eulach.
The confluecne of the Vordertöss and Hintertöss is called Tössscheidi, which is located at a.s.l. on the border between the municipalities of Wald and Fischenthal. The confluence lies west of the Dägelschberg (1267m (4,157feet)), east of the Hüttchopf (1231m (4,039feet)), and north of the Tössstock (1153m (3,783feet))).
The Vordertöss, or Vordere Töss, originates in the canton of St. Gallen. Its source lies south of the Tössstock, on the northern faces of Schwarzenberg (1293m (4,242feet)) and Höchhand (1314m (4,311feet)). It circumvents the Tössstock on its western flank before reaching Tössscheidi.
The Hindertöss, or Hintere Töss, is the longer of the two tributaries. Its source also lies in the canton of St. Gallen but close to the border with the canton of Zurich. The sources is located below Schindelegg (1265m (4,150feet)) and the southern faces of Schindelberghöchi (1234m (4,049feet)) and Dägelschberg. The Hintertoss affluent Chreuelbach originates below Höchhand, on the western faces of the Habrütispitz (1274m (4,180feet)) and Rossegg (1254m (4,114feet)). The Hintertöss passes Tössstock on its northern hillside before joining the Vordertöss at Tössscheidi.
Starting at Tössscheidi, the Töss flows towards north. It meets the main valley of its own name, Töss Valley (German: Tösstal), just south of Steg (the drainage divide between the rivers Töss and Jona is nearby at Gibswil). From Steg, the river turns west, flows through Bauma and then turns north again. West of the village of Turbenthal it runs towards west again, and the valley gets even more ragged than before. Between Steg and Sennhof, the river is followed by the Töss Valley Railway line. The Töss continues south of Eschenberg mountain, Winterthur's Hausberg, before reaching its confluence with the River Kempt. Below, it traverses the city's most western part, just northeast of the Töss, a city mountain. After joining the River Eulach on the western end of Winterthur, the Töss continues for about in a more or less westnorthwestern direction and finally joins the High Rhine at Tössegg, west of Teufen.
Although the High Rhine flows in a mostly westward direction, it flows southward between Schaffhausen and Tössegg. At Tössegg, the Rhine bends sharply towards northwest, passing the village of Tössriederen, and continues westwards again before flowing through Eglisau. The mouth of the Töss lies just a few kilometers south of the mouth of the River Thur. A few kilometers downstream, the River Glatt flows into the High Rhine.
The River Töss was first mentioned around 1483 (German: das Wasser, genannt die Töss, English: 'the waters named Töss'). Its name probably derives from the German verb tosen (English: to roar). Related toponyms are documented earlier, such as Tössegg (locum dictum Tossegge, 1216), Tössriederen (apud Tossriedern, 1277), and the name "Tösser" (dicti Tösserre, 1267).[1]