It rises on Mount Geisflue in the Faltenjura mountains in the upper region of Basel-Landschaft, on the border with Aargau and Solothurn, and joins the Rhine at Augst.

The river supplied drinking water to the Roman city of Augusta Raurica.

To this end, an aqueduct was constructed, which began upstream of today's Liestal.

Two places where the aqueduct can be visited and walked today, are in the Heidenloch district of Liestal and north-east of the sewage treatment plant in Füllinsdorf.

From 1960 onwards, pollution was countered by the construction of sewage treatment plants.