The Aller is a river in Saxony-Anhalt and Lower Saxony, Germany. It is a tributary of the Weser river and 211 km in length.
The river's source is located near Magdeburg in Saxony-Anhalt. From here it runs northwest into Lower Saxony, where the main portions of the river are situated. Important towns along the course of the Aller include (from the source to the mouth): Wolfsburg, Gifhorn, Celle, Verden. A few kilometres west of Verden the Aller joins the Weser river.
