The source of the Altmühl is located close to the city of Ansbach. From here the river runs southeastwards as a narrow brook to enter the Altmühlsee (a lake) north of Gunzenhausen. After leaving Gunzenhausen the river describes a broad curve through the Frankish Alb. It enters the Altmühl Valley Nature Park, which is famous for its natural beauty: The meanders of the Altmühl River have cut deep gorges into the mountains of the Frankish Alb.
The Altmühl passes the cities of Treuchtlingen, Eichstätt and Beilngries. After Dietfurt the river bed was straightened and integrated into a canal connecting the River Main and River Danube (the Rhine-Main-Danube Canal). In spite of protests by conservationistsTemplate:Citation needed the canal was opened in 1992 and has changed much of the eastern Altmühl Valley. The Altmühl finally meets the Danube in Kelheim.