| Bolgenach | |
| Mouth Coordinates: | 47.355°N 9.9202°W |
| Subdivision Type1: | Countries |
| Subdivision Name1: | Germany and Austria |
| Subdivision Type2: | States |
| Subdivision Name2: | Bavaria and Vorarlberg |
| Length Km: | 29.9 |
Bolgenach is a river of Bavaria, Germany and Vorarlberg, Austria. It flows into the Weißach near Krumbach.