The construction of the Fridau was proposed in 1872 by the village doctor, Dr. J. Sidler, and it opened in 1874 as a sanatorium for lung diseases; it was later operated as a health resort. In 1921, the Canton of Solothurn acquired the facility and operated it as a psychiatric clinic, serving as a branch of the Rosegg facility. The facility was closed in 2008.
The facility is located 660 meters above sea level, at the southern foot of the Jura Mountains, in the northern part of the municipality of Egerkingen, outside the built-up area along the road that crosses the first Jura range toward Langenbruck.
