| Krummbach | |
| Subdivision Type1: | Country |
| Subdivision Name1: | Germany |
| Subdivision Type2: | State |
| Subdivision Name2: | Baden-Württemberg |
| Subdivision Type3: | Reference no. |
| Subdivision Name3: | DE: 2338832 |
| Length: | 17km (11miles) |
| Source1 Location: | Into the Zastler Loch at Feldberg |
| Source1 Elevation: | ca. |
| Mouth Location: | into the Dreisam |
| Mouth Elevation: | ca. |
| Basin Landmarks: | Villages: Oberried, Kirchzarten |
| Basin Size: | 30.99 km2 [1] |
| Discharge1 Location: | [2] at its mouth |
| Discharge1 Avg: | 1.0 m3/s |
| Tributaries Right: | Weilersbächle |
| Tributaries Left: | Stollenbach |
| Custom Label: | References |
The Krummbach is a left tributary of the Dreisam in the Southern Black Forest east of Freiburg im Breisgau in the German state of Baden-Württemberg. It is just under 17 kilometres long, In its upper reaches it is better known as the Zastlerbach; in its middle course it is also known as the Osterbach.