| Brunnbach | |
| Source1 Location: | Fellhorn (Chiemgau Alps) |
| Mouth Location: | Großache in the Hagertal |
| Progression: | Großache→ |
| Subdivision Type1: | Country |
| Subdivision Name1: | Austria |
| Subdivision Type2: | State |
| Subdivision Name2: | Tyrol |
| Mouth Coordinates: | 47.636°N 12.4588°W |
The Brunnbach is a river of Tyrol, Austria, in the protected landscape Hefferthorn-Fellhorn-Sonnenberg.
The Brunnbach rises at an altitude of above the Adriatic sea level below the Fellhorn mountain in the Chiemgau Alps and flows with a number of waterfalls in the Kreuzangergraben downstream int the valley. The stream is fed by tributaries from the rifts of the Einfangalm, Hackalm, Martenalm and Weissensteinalm. (Alm: German for Alpine pasture). In a last waterfall above the Bäckenalm, the water again rushes down and collects itself in a lagoon-like basin. In the valley Hagertal between Kössen and Kirchdorf in Tirol, after it reaches as right tributary the Großache.
The distinctiveness of this river is the naturalness of its meandering course and its natural shore vegetation. The stream has a width between 2and. After strong rainfalls, the body swells rapidly and passes over the shores, but flows through the meanders at low speed. Therefore, here the typical fertile wetlands are formed.