Sienhachenbach is an Ortsgemeinde, or municipality, located in the Birkenfeld district of Rhineland-Palatinate, Germany. It functions as a member of a Verbandsgemeinde, which is a specific type of collective municipality used for administrative purposes.
The village belongs to the Verbandsgemeinde Herrstein-Rhaunen. The administrative seat for this collective municipality is located in the town of Herrstein.