The Limmat is a river in Switzerland which rises in the city of Zürich at the north end of Lake Zürich and flows in northwestern direction until it flows after 35 km into the river Aare north of the small town of Brugg and shortly after the mouth of the Reuss.

Its name comes from Linth and Maag the main tributaries of the lake of Zürich before the Linth river control.

Its main tributaries are the Sihl (in Zürich) and the Reppisch (in Dietikon).

The major towns on the Limmat beside Zürich are the much smaller Dietikon, Wettingen , and Baden with smaller villages in-between.

Like many Swiss rivers, it is intensively used for production of hydroelectric power: along its course of 35 km, its fall is used by no less than ten hydroelectric power stations.