The river Suhre (also Sure) is a 34 kilometer long tributary of the river Aare in the Swiss cantons of Lucerne and Aargau. The river sources in 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 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 Ruederche joining at Schöftland, the Uerke joining at Unterentfelden and the Wyna joining at Suhr.