Thur is a 131 km long river in north-eastern Switzerland. Its source is near the mountain Säntis in the south-east of the canton of St. Gallen. In this canton it flows through the Toggenburg region and the town Wil. After Wil it flows through the canton of Thurgau and its capital Frauenfeld. The final 19 km of the river Thur are in the canton of Zürich. It flows into the river Rhine on the border with Germany, south of Schaffhausen.