| Westernach | |
| Mouth Coordinates: | 48.314°N 9.8887°W |
| Subdivision Type1: | Country |
| Subdivision Type2: | State |
| Length: | 6.5km (04miles) |
| Source1 Elevation: | 490m (1,610feet) |
| Mouth Elevation: | 479m (1,572feet) |
| Basin Size: | 256km2 |
Westernach is a river in Baden-Württemberg, Germany. It is created at the confluence of the rivers Rottum and Dürnach near Laupheim. It flows into the Danube near Erbach an der Donau.