The river Moosalb is a left tributary at Fischweier on the border between the municipalities of Marxzell and Karlsbad.

Out of Ettlingen, the Alb leaves the Black Forest and reaches the Upper Rhine Plain.

Afterwards the Alb flows through the so-called Günther Klotz Facilities in the southern part of Karlsruhe – partially being the district border between Bulach and Beiertheim – and thereby forms the core of a popular local recreation area.

In Knielingen, the river turns north-northeast, approximately parallel to the Rhine, and flows through the MiRO oil refinery in a canal.

Shortly before emptying into the Rhine, it is joined to the right side by the relief canal of the river Pfinz.