Fachbach is a municipality in the district of Rhein-Lahn, in Rhineland-Palatinate, in western Germany.

The official website states that the inhabitants fished trouts in former times with a wicker basket they called "Fach".

Recommendable is the "Nieverner Hütte", an iron works on the Fachbacher island Oberau in the Lahn river.

The island Oberau was the location of the Gustav Fudickar "Schlafwohl" (literally: Sleepwell) upholstery and mattress factory (founded 1885) between the 60s and 70s.

In the forest of Fachbach fossils were found and the fauna shows many various butterflies, including very rare specimens.