| Lachsbach | |
| Subdivision Type1: | Country |
| Subdivision Name1: | Germany |
| Subdivision Type2: | State |
| Subdivision Name2: | Saxony |
| Subdivision Type3: | Region |
| Subdivision Name3: | Saxon Switzerland |
| Length: | 3km (02miles), with the Polenz 34.3km (21.3miles) |
| Source1 Location: | Start: Confluence of the Sebnitz and the Polenz near Porschdorf |
| Mouth Location: | Near Wendischfähre into the Elbe |
| Basin Size: | [1] |
| Discharge1 Location: | at Porschdorf I gauge |
| Discharge1 Min: | Average low: |
| Discharge1 Max: | Average high: |
| Custom Label: | References |
The Lachsbach, also called the Rathmannsdorfer Bach, is a river of Saxony, Germany. It is the largest, right-hand tributary of the Elbe in Saxon Switzerland.
The Lachsbach is formed by the merger of its headstreams, the Sebnitz (left, about half the size) and Polenz (right, rather longer) in the Elbe Sandstone Mountains near Porschdorf. The combined confluence section of the two rivers was first recorded in 1543 as die beyde wasser ("the two waters"), a description no longer common today. After only 3km (02miles), the Lachsbach empties into the Elbe above Prossen's winter port near Wendischfähre.