The river Suhre is a 34 kilometer long tributary of the river Aare in the Swiss cantons of Lucerne and Aargau. The river rises in Sempachersee (or Lake Sempach) at an altitude of 504 meters above sea level, and joins the Aare east of the town Aarau at an altitude of 362 meters. The most important side valley is the Ruedertal, which joins the Suhretal (or Suhre Valley) at Schöftland.
In medieval age, the river had several different names: Suron (1036), Suranum flumen (1210), Sure (1241). Today, the name is written without „h“ in the canton of Lucerne, and with „h“ in the canton of Aargau. The most important tributaries are the Ruederchen joining at Schöftland, the Ürke joining at Unterentfelden and the Wyna joining at Suhr.