Eidenau is an unincorporated community in Jackson Township, Butler County, Pennsylvania, United States.

Gist and George Washington traveled through the area in December 1753 after leaving Fort LeBoeuf bound for Williamsburg, Virginia.

[1] However, another source claims that the Harmony Society named Eidenau after a community in Württemberg, Germany.

The Harmonites settled in this region, and constructed a large mill in the Connoquenessing Valley after a small Delaware tribe moved away in 1792.

[2] At the turn of the 20th century, a new cutoff was built by the Pittsburgh and Western Railroad to connect Eidenau with the community of Ribold which was just outside the city of Butler.